Key Publication Review Archive

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NOVEMBER 2021

Publication: Harpain, F, Schlager, L, Hütterer, E, et al. Teduglutide in short bowel syndrome patients – A way back to normal life? JPEN JParenter Enteral Nutr. 2021; 00 1– 10. https://doi.org/10.1002/jpen.2272

Reviewer: Sneha G. Bhat, MD, FACS, CNSC. Assistant Professor of Surgery, UT Southwestern Medical Center, Dallas, Texas.

Why is this paper important? Short bowel syndrome (SBS) is an intestinal failure that occurs due to inadequate absorption and/or digestion of nutrients, often after extensive or multiple intestinal resections. Manifestations of SBS can occur due to loss of intestinal absorptive surface area, removal of the ileocecal valve, or through loss of site-specific endocrine cells, transport processes, or GI hormones.   The subsequent malabsorption of micro or macronutrients, water, and/or electrolytes leads to malnutrition and requires tailored nutrition support for optimization.  The prevalence of SBS is about 3-4 million patients and can occur in approximately 15% of adult patients undergoing intestinal resection.  Given the vast complications associated with SBS, improved understanding of any adjuncts for medical optimization of these patients is crucial. Teduglutide is a dipeptidyl-peptidase, degradation-resistant GLP-2 analogue, which recent literature has shown to improve functional and structural capacity of the intestines with repeated administration . This observational, retrospective study includes 13 patients in their final analysis and looks at various functional and symptomatic responses, nutrition status, as well as adverse events and SBS treatment-related complications. One of the main outcomes was enteral autonomy, or complete independence of parenteral support, whether PN or IVFs. Prior to this study, success rates of enteral autonomy with teduglutide use have ranged from anywhere between 12 -29%.  When these thirteen patients were treated by a multidisciplinary team and teduglutide therapy was utilized, decreased dependence of parenteral support was documented, as well as enteral autonomy in >90% of the cohort. Although a small study, this paper shows that teduglutide may be an effective adjunct in the treatment of SBS with intestinal failure and highlights the need for further larger-scale clinical trials utilizing this medication in an unrestricted clinical setting.

Summary: Glucagon-like peptide 2 (GLP-2) is known to stimulate the growth of intestinal mucosa via stimulation of crypt cell growth, inhibition of enterocyte apoptosis and impedes gastric emptying, stimulates intestinal blood flow, and increases intestinal barrier function . Thus, GLP-2 analogues, such as teduglutide, could potentially aid in intestinal rehabilitation and achieving enteral autonomy. In this retrospective observational study performed at a single tertiary care institution, at the Medical University of Vienna, analysis was performed of all patients with non-malignant SBS with intestinal failure between June 2016 to June 2020, with 13 patients included in the final analysis. These patients underwent a patient-tailored plan developed by a multidisciplinary team consisting of GI surgeons, gastroenterologists and dieticians, and received the approved standard dose of daily treatment with teduglutide (0.05 mg/kg/BW) as part of their therapy. Patient demographics were documented, and outcomes were measured as functional response (parenteral requirements, oral intake, and urinary output), symptomatic response (stool characteristics, dietary habits and sleep disruption), nutrition status response, and adverse events (AEs) or complications. Enteral autonomy, defined as complete independence of even periodic parenteral support, was a main outcome measured, and twenty-four weeks after teduglutide therapy initiation 9 of 13 patients, (69%) reached enteral autonomy with complete discontinuation of PS. Over the total length of follow-up, the rate of patients who reached enteral autonomy increased to 12 of 13 patients (92%). At least one AE occurred in nine of 13 of patients (69%), with the most common complaints being GI related, but no AE led to permanent discontinuation of teduglutide treatment. Temporary dose adjustments or injection interval lengthening were enacted in five patients (38%). One death occurred during the study period (respiratory failure because of systemic scleroderma). Additionally, despite concerns regarding the potential of teduglutide to stimulate tumorigenesis due to its role as an intestinotrophic growth factor, all patients received pre-intervention screening colonoscopies and periodic follow-up colonoscopies, but no polyps or signs of colorectal tumorigenesis was noted.

Commentary: Teduglutide is emerging as a potentially highly effective medication that could aid in reducing parenteral support in SBS patients. Treatment of these patients with intestinal failure by a multidisciplinary team using a patient-tailored unique approach increases the rate of enteral autonomy and decreases overall morbidity in this population. Despite multiple clinical trials showing teduglutide treatment to decrease total burden of parenteral support, the rates of reported enteral autonomy remain <30%, until this paper was able to show a 92% rate of enteral autonomy. It is important to note that this is a retrospective, single-institution study with a small total patient size of only13 individuals. Although this is often the nature when examining rare disease entities, it is difficult to generalize this observational data, especially when further dissecting the study population demographics. Of the 13 patients, an overwhelming majority (8 of 13 patients) are non-geriatric patients with inflammatory bowel disease. In addition, over 75% (10 of 13 patients) have some level of continuity with their colon, rather than an ileostomy or jejunostomy. Additionally, the high rate of inter-individual heterogeneity in the patient population, as well as the small sample size, make this data hard to extrapolate to the general SBS population. Additional clinical studies are required in order to characterize the benefit of teduglutide use in SBS intestinal failure and to verify the findings of this paper. 

References:

  1. Seetharam P, Rodrigues G. Short bowel syndrome: a review of management options. Saudi J Gastroenterol. 2011 Jul-Aug;17(4):229-35. doi: 10.4103/1319-3767.82573. PMID: 21727727; PMCID: PMC3133978.
  2. DiBaise JK, Young RJ, Vanderhoof JA. Intestinal rehabilitation and the short bowel syndrome: Part 1. Am J Gastroenterol 2004;99:1386-95. 
  3. Thompson JS. Comparison of massive vs. repeated resection leading to the short bowel syndrome. J Gastrointest Surg 2000;4:101-4.  
  4. Jeppesen PB, Sanguinetti EL, Buchman A, et al. Teduglutide (ALX-0600), a dipeptidyl peptidase IV resistant glucagon-like peptide 2 analogue, improves intestinal function in short bowel syndrome patients. Gut. 2005;54(9):1224-1231.
  5. Seidner DL, Gabe SM, Lee HM, Olivier C, Jeppesen PB. Enteral autonomy and days off parenteral support with teduglutide treatment for short bowel syndrome in the STEPS trials. JPEN J Parenter Enteral Nutr. 2020;44(4):697-702.
  6. Cani PD, Possemiers S, Van de Wiele T, et al. Changes in gut microbiota control inflammation in obese mice through a mechanism involving GLP-2-driven improvement of gut permeability. Gut. 2009;58(8):1091-1103.


OCTOBER 2021

Publication: Gallastegi, A.D., Gebran, A., Gaitanidis, A., Naar, L., Hwabejire, J.O., Parks, J., Lee, J., Kaafarani, H., Velmahos, G.C. and Mendoza, A.E. Early vs Late Enteral Nutrition in Critically Ill Patients Receiving Vasopressor Support. JPEN J Parenter Enteral Nutr. Accepted Author Manuscript. https://doi.org/10.1002/jpen.2266

Reviewer: Sara A. Hennessy, MD, FACS, CNSC.  Associate Professor of Surgery, Director of Surgical ICU, Director of Nutrition, UT Southwestern Medical Center, Dallas, Texas.

Why is this paper important? The American Society of Parenteral and Enteral Nutrition (ASPEN), the Society of Critical Care Medicine (SCCM) and the European Society of Parental and Enteral Nutrition (ESPEN) recommend the early initiation of enteral nutrition (EN) for the critically ill patients (i.e. < 48hrs). Early EN has been shown to decrease mortality and infectious morbidity. However, there is less clarity in the setting of hemodynamic instability and vasopressor use with some guidelines suggesting holding EN until patients are resuscitated and stable.1-2 Hemodynamic instability and vasopressor use has been shown to alter gastrointestinal physiology and cause acute mesenteric ischemia.3 On the other hand EN, has been shown to be protective in patients receiving vasopressors.4-5 This study retrospectively analyzed a large national database to compare outcomes in patients on vasopressor therapy receiving early versus late EN.  In this propensity matched population for early vs late EN, there was no difference in 28-day hospital mortality.  

Summary: A retrospective review of a national eICU collaborative research database was performed for adult patients requiring vasopressor support and mechanical ventilation within 24 hours of admission and for those patients with a greater than 72-hour admission. The two groups compared were patients that received early and late EN; which, was defined as tube feeding within 48 hours and between 48 hours to 1 week (otherwise NPO).  A 1:1 propensity matching was performed between the early and late EN groups to match baseline characteristics with the primary outcome of 28-day inpatient mortality.  Of the 1701 patients identified, 1148 patients were propensity matched (574 patients in each group).  There was no difference in mortality (HR: 1.15 [0.93-0.1.42]), ventilator-free days or hospital length of stay (LOS).  However, ICU LOS was significantly lower in the early EN group.  Patients in the early EN group also required significantly less renal replacement therapy (OR 0.63 [0.47-0.85]) and a lower likelihood of electrolyte abnormalities (OR 0.48 [0.29-0.78]).  There was no difference in any other in-hospital complications between the early and late EN groups.

Commentary: The initiation of early enteral nutrition in the critically ill has been shown to decrease mortality and infections complications, however, there is uncertainty about its safety in patients on vasopressor therapy.  Current guidelines suggest that enteral nutrition should be held until patients are fully resuscitated and stable.   Hemodynamic instability and vasopressor therapy are believed to have deleterious effects on GI physiology that can lead to acute bowel ischemia. The NUTRIREA-2 trial reported bowel ischemia in 2% (19 patients) receiving early enteral nutrition compared to parenteral nutrition in critically ill patients on vasopressors. 6 In this study Gallastegi et al found that there was no difference in mortality, LOS or ventilator free days but did find that the early EN group had lower ICU LOS and electrolyte abnormalities.  This study had 1 case of acute bowel ischemia.  Although the incidence is low of bowel ischemia, this study is limited by the fact that the eICU database did not include information regarding vasopressor doses or the decision behind why patients received early versus late EN. Current guidelines suggest holding enteral nutrition in patients are being actively resuscitated and/or have escalating doses of vasopressors.  However, most would consider starting EN in patients that are hemodynamically stable despite vasopressor use.  Further studies are necessary to evaluate the impact of early EN in patients who are on vasopressors, stratified by vasopressor dose, hemodynamic stability as well as type of shock.  

References:

  1. McClave SA, Taylor BE, Martindale RG, et al. Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.). Journal of Parenteral and Enteral Nutrition. 2016;40(2):159-211. doi:10.1177/0148607115621863 
  2. Singer P, Blaser AR, Berger MM, et al. ESPEN guideline on clinical nutrition in the intensive care unit. Clinical Nutrition. 2019;38(1):48-79. doi:10.1016/j.clnu.2018.08.037
  3. Reignier J, Boisramé-Helms J, Brisard L, et al. Enteral versus parenteral early nutrition in ventilated adults with shock: a randomised, controlled, multicentre, open-label, parallel-group study (NUTRIREA-2). The Lancet. 2018;391(10116):133-143. doi:10.1016/S01406736(17)32146-3
  4. Khalid I, Doshi P, DiGiovine B. Early enteral nutrition and outcomes of critically ill patients treated with vasopressors and mechanical ventilation. American Journal of Critical Care. 2010;19(3):261-268. doi:10.4037/ajcc2010197 
  5. Kompan L, Kremzar B, Gadzijev E, Prosck M.  Effects of early enteral nutrition on intestinal permeability and the development of multiple organ failure after multiple injury. Intensive Care Medicine. 1999;25(2):157-161. doi:10.1007/s001340050809
  6. Reignier, Jean & Helms, Julie & Brisard, Laurent & Lascarrou, Jean Baptiste & Ait Hssain, Ali & Anguel, Nadia & Argaud, Laurent & Asehnoune, Karim & Asfar, Pierre & Bellec, Frédéric & Botoc, Vlad & Bretagnol, Anne & Bui, Hoang-Nam & Canet, Emmanuel & Silva, Daniel & Darmon, Michael & Das, Vincent & Devaquet, Jérôme & Djibre, Michel & Contentin, Laetitia. (2017). Enteral versus parenteral early nutrition in ventilated adults with shock: a randomised, controlled, multicentre, open-label, parallel-group study (NUTRIREA-2). The Lancet. 391. 10.1016/S0140-6736(17)32146-3.


AUGUST 2021

Publication: Bury C, DeChicco R, Nowak D, Lopez R, He L, Jacob S, Kirby DF, Rahman N, Cresci G. Use of Bedside Ultrasound to Assess Muscle Changes in the Critically Ill Surgical Patient. JPEN J Parenter Enteral Nutr. 2021 Feb;45(2):394-402. doi: 10.1002/jpen.1840. Epub 2020 May 11. PMID: 32391964.

Reviewer: Paul McCarthy MD, CNSC; Associate Professor of Medicine, Director of Cardiovascular Critical Care, West Virginia University Heart and Vascular Institute, Morgantown, West Virginia

Why is this paper important? Loss of muscle mass in the intensive care unit is associated with negative outcomes1. Bedside ultrasound is an excellent tool to assess muscle mass in critically ill patients as it is non-invasive, inexpensive, readily available and easy to perform2. In this study, trained registered dietitian nutritionists (RDNs) used bedside ultrasound (US) to measure the quadriceps muscle thickness (QMLT) to assess muscle loss over a 10-day period in a surgical intensive care unit (SICU). In this study of critically ill surgical patients, a significant rate of QMLT loss occurred over a 10-day period and preexisting malnutrition was a risk factor for QMLT loss. This study suggests that bedside US is a potential tool for RDNs to assess muscle mass and may be more sensitive than ASPEN/AND criteria to assess malnutrition and muscle loss.

Summary: This study took place in the SICU at the Cleveland Clinic. Three RDNs trained in the US protocol measured the QMLT via US at the midpoint and one-third distance between the superior margin of the patella and the anterior superior iliac spine. The QMLT measurements were taken on the day of enrollment and repeated 1 to 2 times over 10 days. Fifty-two critically ill SICU patients and 15 healthy controls were enrolled in the study. The controls were recruited from the Cleveland Clinic campus and measurements from both patient groups were completed by the same protocol. The study patients and controls were similar in age, BMI and gender. The controls showed no decrease in QMLT during the study period, however, the study patients did show a significant rate of QMLT loss over the 10-day period in the SICU with an average percent of muscle loss of 3.2 + 3.8 (p < 0.001) per day at the midpoint and 2.9 + 5.7 (p +0.001) at the one-third landmark. The authors found a higher rate of muscle loss occurred between the second and third measurements. Neither caloric or protein intake had an impact on the rate of muscle loss. However, most patients in the study received greater than 80 percent of their estimated nutrition requirements by the time of their third measurement.

Commentary: Critical illness is associated hypercatabolism, poor nutrition delivery, muscle mass loss and poor outcomes3. Identifying muscle mass loss by physical examination is recommended with dietitians commonly utilizing the nutrition-focused physical examination (NFPE) in practice.  Multiple factors, such as edema, instability, and lines potentially interfere with a quality physical examination. Ultrasound is increasing becoming a part of the physical examination and is being used with increasing frequency for many applications related to nutritional support4,5,6,7,8,9. In this study, trained RDNs measured the quadriceps muscle layer thickness (QMLT) using a specific US protocol in healthy controls and surgical intensive care unit (SICU) patients. Not surprisingly, muscle loss was noted in critically ill SICU patients, however, this was noted even in an absence of an increase in malnutrition severity by ASPEN/AND criteria. US may be a more sensitive tool to diagnosis muscle loss and potentially US will become a tool added to the NFPE? This is not the first article discussing US to access muscle mass or RDNs performing the examinations, however, this is an interesting study highlighting the need for future studies to help guide us on how to integrate the technology into our practice.

References:

  1. Lambell KJ, King SJ, Forsyth AK, Tierney AC. Association of Energy and Protein Delivery on Skeletal Muscle Mass Changes in Critically Ill Adults: A Systematic Review. JPEN J Parenter Enteral Nutr. 2018 Sep;42(7):1112-1122. doi: 10.1002/jpen.1151. Epub 2018 Mar 30. PMID: 29603281.
  2. Tillquist M, Kutsogiannis DJ, Wischmeyer PE, Kummerlen C, Leung R, Stollery D, Karvellas CJ, Preiser JC, Bird N, Kozar R, Heyland DK. Bedside ultrasound is a practical and reliable measurement tool for assessing quadriceps muscle layer thickness. JPEN J Parenter Enteral Nutr. 2014 Sep;38(7):886-90. doi: 10.1177/0148607113501327. Epub 2013 Aug 26. PMID: 23980134; PMCID: PMC4502435.
  3. Tsai JR, Chang WT, Sheu CC, Wu YJ, Sheu YH, Liu PL, Ker CG, Huang MC. Inadequate energy delivery during early critical illness correlates with increased risk of mortality in patients who survive at least seven days: a retrospective study. Clin Nutr. 2011 Apr;30(2):209-14. doi: 10.1016/j.clnu.2010.09.003. Epub 2010 Oct 12. PMID: 20943293.
  4. Jackson SS, Le HM, Kerkhof DL, Corrado GD. Point-of-Care Ultrasound, the New Musculoskeletal Physical Examination. Curr Sports Med Rep. 2021 Feb 1;20(2):109-112. doi: 10.1249/JSR.0000000000000810. PMID: 33560035.
  5. Saugel B, Scheeren TWL, Teboul JL. Ultrasound-guided central venous catheter placement: a structured review and recommendations for clinical practice. Crit Care. 2017 Aug 28;21(1):225. doi: 10.1186/s13054-017-1814-y. PMID: 28844205; PMCID: PMC5572160.
  6. Tsujimoto H, Tsujimoto Y, Nakata Y, Akazawa M, Kataoka Y. Ultrasonography for confirmation of gastric tube placement. Cochrane Database Syst Rev. 2017 Apr 17;4(4):CD012083. doi: 10.1002/14651858.CD012083.pub2. PMID: 28414415; PMCID: PMC6478184.
  7. Gok F, Kilicaslan A, Yosunkaya A. Ultrasound-guided nasogastric feeding tube placement in critical care patients. Nutr Clin Pract. 2015 Apr;30(2):257-60. doi: 10.1177/0884533614567714. Epub 2015 Jan 23. PMID: 25616518.
  8. Deniz O, Cruz-Jentoft A, Sengul Aycicek G, Unsal P, Esme M, Ucar Y, Burkuk S, Sendur A, Yavuz BB, Cankurtaran M, Halil M. Role of Ultrasonography in Estimating Muscle Mass in Sarcopenic Obesity. JPEN J Parenter Enteral Nutr. 2020 Nov;44(8):1398-1406. doi: 10.1002/jpen.1830. Epub 2020 Apr 28. PMID: 32342544.
  9. Lambell KJ, King SJ, Forsyth AK, Tierney AC. Association of Energy and Protein Delivery on Skeletal Muscle Mass Changes in Critically Ill Adults: A Systematic Review. JPEN J Parenter Enteral Nutr. 2018 Sep;42(7):1112-1122. doi: 10.1002/jpen.1151. Epub 2018 Mar 30. PMID: 29603281.


JULY 2021

Publication: Ireland, M., Lo, W., Villarreal, M., Coleman, L., Schubauer, K., Strassels, S., Peters, Z., Woodling, K., Evans, D. and Wisler, J.  Computed Tomography–Measured Psoas Muscle Density as a Predictive Factor for Hypophosphatemia Associated With Refeeding Journal of Parenteral and Enteral Nutrition. 45: 800-809.

Reviewer: Vikram J. Christian, MBBS, CNSC; Assistant Professor of Pediatrics, Division of Pediatric Gastroenterology, University of Minnesota, Minneapolis, MN

Why is this paper important? Although criteria for identification of a patient at risk for refeeding syndrome have been suggested, no reliable biomarkers exist.  Quantity and quality of muscle mass, a marker of physiologic reserve, has been increasingly linked to morbidity and mortality in critical illness.  This study aimed to determine if CT-measured psoas muscle density [a validated marker of nutritional risk] could be used to predict the development of hypophosphatemia, and thereby identify patients at risk for refeeding syndrome.

Summary: This was a retrospective cohort analysis of patients admitted at a single institution, who underwent a surgical procedure and initiation of parenteral nutrition [PN], between August 2014 and March 2016.  Patients who had an abdominal CT scan within the 3 months prior to PN therapy initiation were included in the study.

A total of 109 patients were analyzed.  Psoas muscle density was measured with a Hounsfield Unit Average Calculation [HUAC].  Since there is lack of established normal psoas muscle density values, the patient population was divided into quartiles, with the first quartile having a HUAC value less than 25.  This group was labeled as having "low psoas muscle density” and was comprised of 28 patients.  The remaining 81 patients were labeled as "all others".  Demographic and baseline information including the Charlson Comorbidity Index were recorded.  Baseline laboratory data [prior to initiation of PN], and subsequent values for PN days 1, 2 and 3 were recorded.  Patient outcomes recorded include length of hospital stay, length of ICU stay, days on mechanical ventilation, incidence of low serum electrolyte levels [based on the institution’s normal range].  A t-test of unequal variances was used to compare patients in each cohort.  The authors also established a 1:1 propensity matched analysis based on sex, age and BMI to account for confounding variables.

The authors compared incidence rates of electrolyte derangements among the groups.  Phosphate levels on PN days 1, 2 and 3 were compared across the groups for significant differences.  Percentage change of electrolyte levels from baseline to day 3 was also compared among the cohorts.  Similar analysis was completed for the propensity matched groups, each group consisting of 28 patients.  The authors went on to reclassify their patients according to BMI, into 3 groups [BMI less than 20 kg/m2, BMI 20-30 kg/m2, BMI greater than 30 kg/m2], and looked at phosphate values at baseline, on PN days 1, 2 and 3, and percent change of phosphate value from baseline.

The authors found that patients with low psoas muscle density were older and had a greater BMI. On introduction of PN, this group had significantly lower serum phosphate levels on PN days 2 and 3, as well as a significant decline in phosphate levels from baseline, when compared to the group with higher psoas muscle density.  Despite this decline in phosphate levels, hypophosphatemia did not occur significantly more often in the low psoas muscle density group. Once confounding variables were accounted for by means of propensity matching, there remained a significant decline in phosphate levels from baseline in the low muscle density group. It was also found that patient in the low psoas muscle density group were on ventilation support for a greater duration. 

When these patients were stratified according to BMI, there were no statistical differences noted between the 3 new cohorts in phosphate values and trends.

The authors conclude by suggesting that a HUAC value of less than 25 [that the authors used to identify patients with low psoas muscle density] could serve to identify patients at highest risk for developing hypophosphatemia upon initiation of PN.  They also concluded that BMI alone was not predictive of the development of hypophosphatemia.

The authors acknowledge several limitations in their study including small cohort size, retrospective design and wide range of indications for surgical intervention. Of note, the authors did not assess the effect of electrolyte replacement therapy [whether intravenous or oral] in their analysis.

Commentary: Refeeding syndrome is defined as the potentially fatal shifts in fluids and electrolytes that may occur in malnourished patients receiving artificial refeeding [whether enterally or parenterally].1 The earliest recognized occurrence of refeeding syndrome was in Cabrera Island during the early 1800s.  Prisoners of war from the Battle of Bailen of the Peninsula War were fed infrequently due to limited food sources on the island and delayed food shipments.  On arrival of the delayed food shipment, some inhabitants of the island consumed 4 days of rations in a short span of time. It is estimated at 500-900 individuals died during this famine, or due to refeeding syndrome that resulted from rapid reintroduction of nutrition.2

Refeeding syndrome is thought to occur due to increased insulin and decreased secretion of glucagon in response to glycemia that occurs on refeeding.  Insulin stimulates production of glycogen, fat and protein.  Phosphate, magnesium and thiamine are utilized in this process.  Insulin also causes influx of potassium into cells.  These processes lead to a decrease in serum levels of phosphate, potassium and magnesium.  Clinical features of the syndrome are thought to be a direct consequence of these electrolyte deficits.1

According to Mehanna at al, patients at high risk of refeeding syndrome include those with anorexia nervosa, chronic alcoholism, uncontrolled diabetes mellitus, chronic malnutrition, oncology patients, postoperative patients, elderly patients, long-term users of antacids and diuretics.1 The National Institute for Health and Care Excellence (UK) have also established criteria for identifying a patient at risk for refeeding.3 The ASPEN/Society for Critical Care Medicine Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient (2016) state that attention to refeeding is especially important for the patient with alcoholism, weight loss, low BMI, prolonged NPO status.  The guidelines also state that refeeding risk is higher with initiation of PN [compared to enteral nutrition]. It is recommended that enteral feeding be advanced slowly, and initiation of PN be protocolized.

Although criteria for identification of the patient at risk of developing refeeding syndrome are used in clinical practice, no reliable biomarker exists. CT cross-sectional psoas muscle images are increasingly used to identify sarcopenia, and low muscle density.  Muscle quantity and quality, as detected on these images, is a validated marker of nutritional risk.5 It is now known that critically ill patients with sarcopenia on admission frequently have poor outcomes.6 This study attempts to determine if CT-measured psoas muscle density could be used as a marker to predict the development of hypophosphatemia and refeeding syndrome.

Despite the detection of a statistically significant difference in phosphate values on days 2 and 3 of PN, as well as a decline in phosphate values from baseline, the incidence of hypophosphatemia is not significantly increased in the low psoas muscle group.  The authors acknowledge the lack of inclusion of electrolyte supplementation in their analysis as a limitation. This exclusion does have the potential to skew the results.  Therefore, prospective studies that take electrolyte supplementation [enteral and parenteral] into consideration will be required to further validate the Hounsfield unit average calculation value of less than 25 as a marker to identify patients at risk of refeeding syndrome. In conclusion, this well-designed study paves the way for future studies aimed at identifying patients at risk for refeeding syndrome based on abdominal CT images.

References:

  1. Mehanna HM, Moledina J, Travis J. Refeeding syndrome: what it is, and how to prevent and treat it. BMJ. 2008 Jun 28;336(7659):1495-8. doi: 10.1136/bmj.a301. PMID: 18583681; PMCID: PMC2440847.
  2. Smith, D. The Prisoners of Cabrera: Napoleon's Forgotten Soldiers 1809-1814. 2001.
  3. Nutrition support for adults: oral nutrition support, enteral tube feeding and parenteral nutrition. London: National Institute for Health and Care Excellence (UK); 2017 Aug. PMID: 31999417.
  4. McClave SA, Taylor BE, Martindale RG, Warren MM, Johnson DR, Braunschweig C, McCarthy MS, Davanos E, Rice TW, Cresci GA, Gervasio JM, Sacks GS, Roberts PR, Compher C; Society of Critical Care Medicine; American Society for Parenteral and Enteral Nutrition. Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.). JPEN J Parenter Enteral Nutr. 2016 Feb;40(2):159-211. doi: 10.1177/0148607115621863. Erratum in: JPEN J Parenter Enteral Nutr. 2016 Nov;40(8):1200. PMID: 26773077.
  5. Wojda, T.R., Cardone, M.S., Lo, W.D. et al. Ultrasound and Computed Tomography Imaging Technologies for Nutrition Assessment in Surgical and Critical Care Patient Populations. Curr Surg Rep 3, 21 (2015). https://doi.org/10.1007/s40137-015-0099-9
  6. Zhang XM, Chen D, Xie XH, Zhang JE, Zeng Y, Cheng AS. Sarcopenia as a predictor of mortality among the critically ill in an intensive care unit: a systematic review and meta-analysis. BMC Geriatr. 2021 Jun 2;21(1):339. doi: 10.1186/s12877-021-02276-w. PMID: 34078275; PMCID: PMC8173733.


JUNE 2021

Publication: Zusman O, Kagan I, Bendavid I, Theilla M, Cohen J, Singer P.  Predictive equations versus measured energy expenditure by indirect calorimetry: A retrospective validation . Clinical Nutrition. 2019;38(3):1206-1210. doi: Zusman O, Kagan I, Bendavid I, Theilla M, Cohen J, Singer P. .

Reviewer: Matthew Ewy, MD, RD, CNSC

Why is this paper important? Indirect calorimetry (IC) is recognized as the “gold standard” to determine caloric expenditure in patients. Despite its validity, indirect calorimetry is not widely utilized in the intensive care unit setting due to the need for specialized equipment, increased cost, and the need for the patient to be in an undisturbed or “steady state” for an accurate measurement.1 Despite its accuracy, indirect calorimetry only provides an estimate at a particular moment in the patient’s clinical course. It is well known that different phases of critical illness and patient heterogeneity result in frequent changes in caloric need, thereby making the indirect calorimetry measurement truly valid for only the point in time it was measured. 

Given the limitations in access and testing for IC, it is common for clinicians to rely on predictive equations to determine caloric expenditure and nutritional needs. Numerous equations have been developed to replace indirect calorimetry as the new “gold standard.” An accurate equation would be a widely available and cost-effective tool for addressing the caloric needs of a critically ill patient. However, multiple studies validating their clinical utility are often faced with significant limitations such as small sample size, one caloric measurement, or comparing indirect calorimetry to a few equations. Patient heterogeneity and type of critical illness further complicate the accuracy of caloric need. 

The study being reviewed was conducted to help address the limitations of previous studies by comparing multiple predictive equations in patients who underwent more than one indirect calorimetry measurement. 

Summary: This study is a single-center observational study involving 1440 intensive care patients undergoing indirect calorimetry and compared to multiple predictive equations to validate their accuracy for clinical use. All patients underwent up to 5 indirect calorimetry measurements during their hospitalization for a total of 5847 measurements. All measurements were compared to the eight most common caloric predictive equations (25kcal/kg, Harris-Benedict, Penn State Equation, Ireton Jones Equation, Faisy Equation, Mifflin St-Joer Equation, and the Jolliet ESCIM Equation). Agreement between indirect calorimetry and the predictive equations was defined as 85-115% resting energy expenditure. The percent difference, absolute difference, and correlation coefficient were also evaluated. 

The average age was 58 years +/- 19 years, with 65% subjects being male. Most patients were surgical or sepsis related intensive care unit admissions. The average resting energy expenditure per patient was 1891 +/- 506 kcals per day. The Faisy equation demonstrated the least mean difference from IC, and the Harris-Benedict with a stress factor of 1.3 had the highest correlation and agreement. However, no equation consistently demonstrated agreement with >50% of the IC measurements. Additionally, the indirect calorimetry closest to intensive care unit admission performed worse across all parameters with agreement <50% of the time to later IC measurements. 

Commentary: This article compared the validity of numerous predictive equations in a large sample size of patients. This study highlighted the inaccuracy of these equations and demonstrated that the earliest indirect calorimetry measurement had more significant variation in caloric accuracy. While the study results are not surprising, it further underscores the challenges of nutrition in critical illness. 

The use of indirect calorimetry has been under constant debate over the years. Wischmeyer et al. discussed that indirect calorimetry is vital in determining an objective marker for nutritional assessment.2 They also note the limitations of predictive equations and how over and underfeeding in critical illness are associated with poor ICU outcomes. Other patient factors such as morbid obesity, sarcopenia, hypermetabolism, and specific diseases alter resting energy expenditure and make indirect calorimetry challenging to estimate.

On the contrary, McClave et al. discuss how a precise measurement for caloric expenditure is unnecessary as the paradigm of feeding in critical illness has changed over the recent years.3 Recent literature suggests that a high protein and hypocaloric feeding regimen early in acute illness maximizes clinical benefit over the precision of resting expenditure.4 Furthermore, a high degree of variability between calorimeter devices, requiring specialty-trained respiratory therapists, and lack of consensus on procedure protocol complicate the “gold standard” test by creating a sense of inaccuracy of the test itself. Wischmeyer et al. discuss a new-generation indirect calorimeter (Q-NRG by Baxter and COSMED, Inc) that shows promise with its improved accuracy and ease of use compared to previous devices. This device may help address some of these issues with the accuracy of indirect calorimetry.

While not answering the question of when IC is needed to titrate nutrition or high protein hypocaloric feeding based on predictive equations is best for patients, the study highlights the discordance between predictive equations and measured metabolic needs. Nevertheless, if IC is not widely utilized and understood by clinicians, guidelines based on these tests will not be effectively implemented. However, accuracy may not be the answer for every patient. Perhaps indirect calorimetry should be reserved for patients with high clinical suspicion that predictive equations would be out of scope for an appropriate assessment. Implementation of IC would be used to prevent over and underfeeding in complex patients or utilized in patients with prolonged intensive care courses as IC measurements in this study did change throughout the hospitalization. Following general rules such as high protein, hypocaloric feeding in early critical illness may be the best approach to improving outcomes over precise caloric measurements. This study highlights the limitations of comparing indirect calorimetry to predictive equations. While there may never be harmony between the two, with further research, we may better understand when we need precise measurements to tailor nutrition or when we may be able to meet nutritional needs based on rough estimation.  

References:

  1. Delsoglio M, Achamrah N, Berger MM, Pichard C. Indirect calorimetry in clinical practice. J Clin Med. 2019;8(9):1387.
  2. Wischmeyer PE, Molinger J, Haines K. Point‐Counterpoint: Indirect Calorimetry Is Essential for Optimal Nutrition Therapy in the Intensive Care Unit. Nutr Clin Pract. 2021;36(2):275-281.
  3. McClave SA, Omer E. Point‐counterpoint: Indirect calorimetry is not necessary for optimal nutrition therapy in critical illness. Nutr Clin Pract. 2021;36(2):268-274. doi:https://doi.org/10.1002/ncp.10657
  4. Patel JJ, Martindale RG, McClave SA. Controversies surrounding critical care nutrition: an appraisal of permissive underfeeding, protein, and outcomes. J Parenter Enter Nutr. 2018;42(3):508-515.


MAY 2021

Publication: Microbiome connections with host metabolism and habitual diet from 1,098 deeply phenotyped individuals . Nature Medicine. 2021 Feb;27(2):321-332. doi: 10.1038/s41591-020-01183-8. Epub 2021 Jan 11. PMID: 33432175.

Reviewer: Jose M. Pimiento MD, FACS

Why is this paper important? Over the last 10 years the gut microbiome has been recognized as an important determinant of health,1 however, comprehensive analyses of the impact of diet on the microbiome composition are lacking. This research is a prospective study that uses the power of complex analytic methodology of a large multiomic dataset to give us a more complete picture of the interactions between diet, microbiome, health status and metabolic performance. Specifically asking the question of how a subject’s usual diet can affects the microbiome, and how this microbiome, in return, can affect metabolic performance in such subject.

Summary: These are the results of the Personalized REsponse to DIetary Composition Trial (PREDICT1) trial, a multinational study with an overall objective “to predict glucose, insulin, lipid and other postprandial responses to foods based on the individual’s characteristics, including molecular biomarkers and lifestyle factors as well as the nutritional composition of the food”.2 To this end a single arm, single blinded study was conducted from 2018 to 2019 that included samples from 1102 subjects, 1002 “the discovery set” from the UK and 100 “the validation set” from the US. To account for host genetic impact on the microbiome subjects were enrolled from the TwinsUK longitudinal cohort (480 participants). The study collected detailed baseline demographic, clinical and dietary data. The interventions: On day 1 baseline stool samples and blood work including fasting cardiovascular health blood biomarkers were obtained. Then the subjects were given a standardized metabolic challenge breakfast, followed by serial postprandial blood work to evaluate the metabolic response to such diet. From day 2-14 of the study the subjects were provided with standard meals for home; daily monitoring was provided including continual glucose monitoring and cards for collection of capillary blood samples.  Of the 1102 subjects, 1098 subjects had microbiome collection, including 105 subjects with serial samples (more than 14 days apart). Their results are fascinating and very complex and worth reviewing in detail. Here I will describe some of their more salient findings.

  • MicrobiomeDiversity: Low microbiome diversity was directly associated with markers of poor health status such as increased visceral fat and higher BMI. Microbiome diversity was positively correlated with baseline markers of good cardiovascular health. There was very limited impact on host genetic characteristics to account for microbiome diversity.
  • Dietary Habitsand Microbiome: The type of usual diet consumed by the study subjects correlated with strains of bacteria found on their stool samples.  When the diet was categorized on “more or less” healthy plant or animal based diet there was segregation of the strains of bacteria found on such stool samples. Showing a strong correlation between baseline diets and microbiome.
  • Obesity andMicrobiome: The “obesity related microbiome signature” was predicted in the discovery set and confirmed with the validation set and was consistently reproduced across multiple publicly available microbiome data sets.
  • Metabolismand microbiome: Fasting metabolic markers (i.e. blood pressure, LDL, triglycerides, fasting glucose) correlated differentially with specific microbiome clusters, while some pro-inflammatory markers (i.e. polyunsaturated fatty acids, omega 6) were associated with other clusters. Moreover, a “healthy microbiome signature for cardiovascular disease” could be identified based on such associations. Additionally, the preponderant microorganisms found on the microbiome of the subjects predicted metabolic responses to dietary intake specially related with lipid metabolism.
  • Microbiome signature andcardiovascular health: Consistently “favorable species of bacteria” were seen with positive correlation with healthy dietary indexes, negative correlated with markers of cardiovascular risk and positively correlated with healthy metabolic responses to diet (i.e. P. copri,Firmicutes CAC:95, F. pausnitzii among others).  Conversely the presence of other “less beneficial bacteria” were seen consistently associated with increased cardiovascular risk markers and obesity (i.e. Clostridia, R. gnavus, F.plautii among others) 

Commentary: This fascinating work is a tour de force that provides the field of microbiome research with a new conceptual framework, with the utilization of a multiomic approach that requires complex computational models for its analysis. It provides confirmation of previous literature findings in the field and expands on the complex interactions between diet and the microbiome. Additionally, it provides provocative data for future research aimed at designing specific dietary interventions to modify the microbiome and positively impact cardiovascular health.

References:

  1. Le Chatelier E, Nielsen T, Qin J, et al. Richness of human gut microbiome correlates with metabolic markers. Nature. 2013 Aug;500(7464):541-6.
  2. S Berry, D Drew, I Linenberg et al. Personalised REsponses to DIetary Composition Trial (PREDICT): an intervention study to determine inter-individual differences in postprandial response to foods, 14 January 2020, PROTOCOL (Version 1) available at Protocol Exchange [https://doi.org/10.21203/rs.2.20798/v1]


APRIL 2021

Publication: A double-blind phase III trial of immunomodulating nutritional formula during adjuvant chemoradiotherapy in head and neck cancer patients: IMPATOXAmerican Journal of Clinical Nutrition. 2020 Dec 10;112(6):1523-1531. doi: 10.1093/ajcn/nqaa227. PMID: 32936874.

Reviewer: Vijaya Surampudi, MD, MS

Why is this paper important? Head and neck cancer (HNC) accounts for 3% of the malignancies in the United States(1). The most common sites for HNC are the oral cavity, the pharynx and the larynx which are all contribute to the process of mastication. The therapeutic approach for HNC involves a combination of surgery, radiotherapy and chemotherapy and these treatments can result in mucositis, odynophagia, dysphagia, xerostomia, dysgeusia, nausea, vomiting, and anorexia. The multimodal treatment approach to HNC can also contribute decreased oral intake resulting in malnutrition(2). The severity of the adverse side effects may contribute to the need for enteral nutrition. Many patients would prefer to remain on oral nutritional supplements if side effects could be managed or prevented. This study investigates the use of an immunonutrient supplement to help reduce severe side effects resulting from treatment with cisplatin and concomitant radiotherapy. 

Summary: This study was a double-blind phase III multicenter trial involving 180 HNC patients who were eligible for chemoradiation after surgery with curative intent. The patients were assigned to drink oral supplementation three times/day 5 days prior to each cycle of cisplatin and randomized to the immunonutrient supplement enriched with L-arginine, omega 3 fatty and ribonucleic acids (treatment arm) or an isocaloric isonitrogenous supplement (control group). There were 90 patients in each arm and four patients were excluded in each arm due to ineligibility, consent withdrawal or incomplete chemoradiation therapy. Median age was 58 years old, 82.8% male and tumor localization was mainly oral cavity and oropharynx. 

Primary objective of the study was to evaluate efficacy of the immunonutrient supplement on severe mucositis. Secondary objectives included compliance to oral supplementation, progression-free survival and overall survival. At one month, after terminating chemoradiotherapy, the immunonutrient supplement failed to reduce severe mucositis. Grade 3-4 mucositis was reported in 33.7% in the treatment arm and 34.9% in the control group. Overall no difference was observed for severe toxicities reported during chemoradiation treatment between the two arms. After a median follow up of 38.3 months (95% CI: 37.9, 38.6 months) no significant difference was noted in overall survival or progression-free survival.  

However, the study did note improvements in overall survival and progression to free survival in patients who were >75% compliant with the immunonutrient supplement. Of the 172 patients treated with chemoradiation, 112 patients (65%) were classified with >75% compliance. Of that 50.9% took the immunonutrient supplement.  In this group overall survival was significantly improved in the immunonutrient group (81%; 95% CI: 67%, 89%) compared with controls (61%; 95% CI: 46%, 73%; p=0.034), as well as progression free survival (73%; 95% CI: 58%, 83% compared with 50%; 95% CI: 36%, 63%; p= 0.012).  

Commentary: The use of supplements in addition to standard cancer treatment regimens to reduce adverse side effects and improve overall survival is an active area of cancer research. The intervention with the immunonutrient supplement did not reduce severity of mucositis during chemoradiation but noted improvement in overall survival and progression-free survival who were compliant with the supplement. A major challenge in this study was compliance was self reported by the patient without correlation with biomarkers. It is possible the lack of effectiveness to reduce severity of mucositis was related to lack of nutritional counseling in the study design. Adequate protein intake is linked with reduced severity of mucositis. Studies published with HNC patients that nutritional counseling in conjunction with oral nutritional supplements resulted in better protein intake and improved treatment tolerance(3). Providing a nutritional supplement without nutritional counseling may have contributed to lack of improvement in mucositis. In addition, it would be of interest to review the data on the patients’ body weight and body composition through the study duration. Weight loss and sarcopenia in HNC and can possible predict negative clinical outcomes and treatment toxicity(4). Changes in body composition could be linked to the positive outcomes of survival noted in this study.

This trial highlights the need for ongoing investigations of types of oral nutritional supplements, ideal time of administration during the clinical course and determining which biomarkers are important prognostic markers for the clinical course in HNC. 

References:

  1. R. L. Siegel, K. D. Miller, H. E. Fuchs, A. Jemal, Cancer Statistics, 2021. CA: A Cancer Journal for Clinicians 71, 7-33 (2021).
  2. A. Yanni et al., Malnutrition in head and neck cancer patients: Impacts and indications of a prophylactic percutaneous endoscopic gastrostomy. European Annals of Otorhinolaryngology, Head and Neck Diseases 136, S27-S33 (2019).
  3. E. Cereda et al., Nutritional counseling with or without systematic use of oral nutritional supplements in head and neck cancer patients undergoing radiotherapy. Radiotherapy and Oncology 126, 81-88 (2018).
  4. B. Ferrão et al., Body composition changes in patients with head and neck cancer under active treatment: a scoping review. Supportive Care in Cancer 28, 4613-4625 (2020).


MARCH 2021

Reviewer: Chet A. Morrison, MD, FACS, FCCM

Reference: David G. A. Williams, Tetsu Ohnuma, Krista L. Haines, Vijay Krishnamoorthy, Karthik Raghunathan, Suela Sulo, Bridget A. Cassady, Refaat Hegazi and Paul E. Wischmeyer. Association between early postoperative nutritional supplement utilisation and length of stay in malnourished hip fracture patients. British Journal of Anaesthesia Vol. 126 Issue 3p 730–737 Published online: January 27, 2021

Why is this paper important? Substantial evidence exists that patients who have fallen and sustained hip fractures have a significant incidence of malnutrition. There is also substantial evidence that malnutrition is a significant risk factor for adverse outcome in this population, as it is for the general surgical and medical population. Current nutritional guidelines from the European Society of Parenteral and Enteral Nutrition (ESPEN) recommend Oral nutritional supplementation in geriatric patients suffering from malnutrition or who are at risk for malnutrition, although they note that several meta-analyses and randomized controlled trials have not demonstrated a positive effect on mortality. Similarly, ASPEN guidelines from 2011 recommended nutritional assessment in hospitalized patients and nutrition support intervention in patients identified by screening and assessment as at risk for malnutrition or malnourished and suggested that it may improve clinical outcomes. Positive outcomes seem to be found in rates of readmission and quality of life. There is indirect evidence of improved outcomes in patients given nutritional support but direct evidence of the benefit in the population of hip fracture patients can be elusive.

Summary: This was a sponsored study using a commercially available database that identified a retrospective cohort of malnourished hip/femur fracture patients undergoing surgery from 2008 to 2018. The primary outcome was hospital length of stay. Secondary outcomes included infectious complications, hospital mortality, ICU admission, and costs. After identifying these patients, the authors were able to identify those given oral nutritional supplementation from this database. The authors then did propensity matching (1:1) and univariable analysis to assess whether the ONS improved outcomes in patients who received compared to propensity matched controls who did not.
The authors found that out of 160 151 hip/femur fracture surgeries identified within their database, coded-malnutrition prevalence was 8.7%. Early postoperative nutritional supplementation (by hospital day 1) occurred in 1.9% of all patients and only 4.9% of malnourished patients. Propensity score matching demonstrated early nutritional supplements were associated with significantly shorter length of stay (5.8 [6.6] days vs 7.6 [5.8] days; P<0.001) without increasing hospital costs. No association was observed between early nutritional supplementation and secondary outcomes.

Commentary: I think this is a significant study that deserves to be known by all providers who are caring for these elderly, often malnourished, and in my experience impressively frail patients. It is alarming that so few malnourished patients are getting oral nutritional supplementation, and it makes intuitive sense, given that many of these patients are transferred to rehabilitation after their hospital stay, that they would recover quicker and regain the strength needed to undergo rehabilitation if they are given oral supplementation. The study does have the limitations inherent in any retrospective cohort study and in addition has some commercial bias as the principle investigator has a funded industry grant; in addition propensity matching can partially overcome the confounding factors associated with retrospective databases, but only partially; propensity score analyses have the limitation that remaining unmeasured confounding variables may still be present, thus leading to biased results. Also another limitation of propensity score methods is that the analysis does not “fix” other potential methodologic biases that may exist, such as time of receiving oral  nutritional supplementation that may bias the results, or, obscure real outcome differences that nutritional supplementation would be expected to achieve. Nevertheless, the study conclusions that there is at least an association between oral nutritional supplementation and shorter length of stay, and this can be done without significantly increasing costs, is a sound one. Furthermore, any randomized control trial that would have a group in which oral nutritional supplementation is not given to patients at risk for malnutrition would raise significant ethical concerns and is thus unlikely at this time. Thus we are left with these retrospective large studies that I believe meet the level of evidence necessary to support ‘optimizing’ the nutrition of patients who are admitted to the hospital with hip fractures and undergo repair, as well as a base that I hope will allow us to refine our methods of nutritional supplementation in the future to improve ever better outcomes.

References:

  1. Volkert D, Beck AM, Cederholm T, et al. ESPEN guideline on clinical nutrition and hydration in geriatrics. Clin Nutr 2019; 38: 10e47.
  2. Mueller C et al A.S.P.E.N. Clinical Guidelines Nutrition Screening, Assessment, and Intervention in Adults. JPEN 35, (1) January 2011 pp 16-24.
  3. Koren-Hakim T, Weiss A, Hershkovitz A, et al. The relationship between nutritional status of hip fracture operated elderly patients and their functioning, comorbidity and outcome. Clin Nutr 2012; 31: 917e21.
  4. Gregory A. Nuttall, M.D.; Timothy T. Houle, Ph.D. Liars, Damn Liars, and Propensity Scores Anesthesiology January 2008, Vol. 108, 3–4.


FEBRUARY 2021

Reviewer: Michael Mueller, MD,  Senior Associate Consultant, General Internal Medicine, Mayo Clinic, Rochester, MN

Reference: Pedro L Valenzuela, Alejandro Santos-Lozano, Alberto Torres Barrán, Pablo Fernández-Navarro, Adrián Castillo-García, Luis M Ruilope, David Ríos Insua, José M Ordovas, Victoria Ley, Alejandro Lucia, Joint association of physical activity and body mass index with cardiovascular risk: a nationwide population-based cross-sectional study, European Journal of Preventive Cardiology, 2021, zwaa151, https://doi.org/10.1093/eurjpc/zwaa151

Why is this paper important? Individuals with overweight or obese BMIs have increased risk of cardiometabolic comorbidities when compared to normal weight individuals. Multiple studies have provided evidence that patients with low cardiorespiratory fitness levels are at increased risk for both cardiovascular and all-cause mortality when compared to those with higher cardiorespiratory fitness levels, regardless of BMI. Several studies have suggested that risk of cardiovascular mortality in overweight and obese patients is significantly lower in patients with higher cardiorespiratory fitness levels. This has resulted in the proposal of a “fat but fit paradox”, in which higher cardiorespiratory fitness levels mitigate the negative effects of obesity on cardiovascular health outcomes. It has been suggested that health guidance and public health policy should emphasize increasing physical activity levels instead of weight loss.

Summary: This was a Spanish cross-sectional study of 527,662 insured patients between the ages of 18 to 64. Data was collected from chart review of routine medical examinations. Patients were categorized based on BMI (normal weight, overweight, and obese), physical activity levels (inactive, insufficiently active, and active, based on WHO physical activity recommendations for adults), and presence of diabetes, hypercholesterolemia, and hypertension. Logistic regression was used to determine associations, and the model was adjusted for age, gender, smoking status, home address, and date of examination.  

Overall, the sample size was 68% male with a mean age of 42. 42% of patients were normal weight, while 41% were overweight and 18% were obese, respectively. 63.5% of patients self-reported themselves as inactive, whereas 12.3% reported insufficient activity and 24.2% reported regular activity. 30% of patients had hypercholesterolemia, 15% had hypertension, and 3% had diabetes. Patients who were overweight and obese had significantly increased odds of hypercholesterolemia, diabetes, and hypertension, regardless of activity level. Odds for diabetes and hypertension increased significantly for obese patients when compared to overweight patients across all activity levels. Patients who were active in each BMI class had significantly decreased odds of hypertension and diabetes when compared to insufficiently active and inactive patients, respectively, in a physical activity dose-dependent manner. Patients who were both active and obese had two times increased odds for hyperlipidemia, five times increased odds for hypertension, and four times increased odds for diabetes respectively, when compared to inactive normal weight patients.  

Commentary: Limitations of the study include its cross-sectional nature, as correlation does not imply causation. In addition, it should be noted that the study took place in Spain, where diet, physical activity levels, and prevalence of obesity, diabetes, hypertension, and hypercholesterolemia differ from the United States.

Overall, however, these data suggest that both physical activity and weight loss are important in mitigating cardiovascular morbidity. Physical activity may be especially important in decreasing risk of hypertension and diabetes. However, the increased odds of cardiometabolic comorbidities in obese active patients when compared to normal weight inactive patients suggest that increased BMI is an independent risk factor, regardless of activity level. Health guidance to reduce cardiovascular morbidity and mortality should include weight loss recommendations in overweight and obese patients alongside recommendations for increased physical activity. 

References:

  1. Ortega FB, Ruiz JR, Labayen I, Lavie CJ, Blair SN. The Fat but Fit paradox: what we know and don't know about it. Br J Sports Med. 2018 Feb;52(3):151-153. doi: 10.1136/bjsports-2016-097400. Epub 2017 Jun 5. PMID: 28583992.
  2. Barry VW, Caputo JL, Kang M. The Joint Association of Fitness and Fatness on Cardiovascular Disease Mortality: A Meta-Analysis. Prog Cardiovasc Dis. 2018 Jul-Aug;61(2):136-141. doi: 10.1016/j.pcad.2018.07.004. Epub 2018 Jul 5. PMID: 29981352.
  3. Barry VW, Baruth M, Beets MW, Durstine JL, Liu J, Blair SN. Fitness vs. fatness on all-cause mortality: a meta-analysis. Prog Cardiovasc Dis. 2014 Jan-Feb;56(4):382-90. doi: 10.1016/j.pcad.2013.09.002. Epub 2013 Oct 11. PMID: 24438729.

JANUARY 2021

Reviewer: Arsalan Khan, MD, Nutrition Support Service UICOMP/St. Francis Medical Center Peoria, Illinois

Reference: Xue Z, Coughlin R, Amorosa V, Quinn R, Schiavone P, Stoner N, et al. Factors Associated With Central Line-Associated Bloodstream Infections in a Cohort of Adult Home Parenteral Nutrition Patients. Journal of Parenteral and Enteral Nutrition. 2020 Nov;44(8):1388–96.

Why is this paper important? Infectious complications of parenteral nutrition (PN) are amongst the most frequent causes of morbidity and rehospitalization in home parenteral nutrition patients. The exact cost of catheter related blood stream infections (CLABSI) in dollars terms is challenging to quantify but could be upwards of 30,000 dollars per admission depending on severity and length of stay. Given the frequency of infections in PN patients, the cost can quickly add up to significant sums over the course of therapy.1 Despite how common CLABSIs are, there remains no accurate way to predict risk. The heterogeneous nature of the HPN population has led to conflicting data, even for the most fundamental issue, such as the type of catheter used. This study, in particular, reports a unique observation: patients with low BMI (<18.5) may have up to six times greater risk of CLABSI.

Summary: This study is an observational study attempting to identify patient factors/characteristics in home parenteral nutrition patients that predispose them to CLABSI. The patient population consists of patients under the care of the HPN service at the University of Pennsylvania Hospital from January 1, 2018, to June 30, 2019. The authors reviewed all medical records for basic demographics, diagnosis, experience with TPN, type of catheter (including the number of lumens), prior CLABSI, history of ostomy or wound, immunosuppression, and depression/anxiety. Bivariate associations between predictors and CLABSI outcome were assessed using chi-square or Fisher exact tests/t-test depending whether the predictor was categorical or continuous. The authors found presence of ostomy, tunneled/implanted catheter, and BMI less than 18 was associated with an increased risk of CLABSI.  

Commentary: While many studies have been conducted to assess risk factors predisposing patients to CLABSIs, this seems to be the first to describe BMI as an independent predictor of it. The authors also found tunneled/implanted ports to be associated with more infections than PICC lines. This, however, remains a point of contention, with various studies reporting either increased or decreased incidence of CLABSI associated with PICC lines. As per the ASPEN 2019 catheter selection guidelines, there remains mostly weak evidence regarding the risk of infection and mechanical complications based on catheter type. The situation is made even more confusing when comparing valved with non-valved central venous catheters, with one study reporting higher rates of CLABSI with valved Groshong catheters.2 In the absence of strong evidence to guide decision-making, the best course of action is to individualize therapy to a patients' unique circumstances.  

References:

  1. Analysis of Healthcare Institutional Costs of Pediatric Home Parenteral Nutrition Central Line Infections Raphael, Bram P.∗; Hazekamp, Christina∗,‡; Samnaliev, Mihail†; Ozonoff, Al‡,§ Author Information Journal of Pediatric Gastroenterology and Nutrition: October 2018 - Volume 67 - Issue 4 - p e77-e81 doi: 10.1097/MPG.0000000000002058
  2. Gleeson NC, Fiorica JV, Mark JE, Pinelli DM, Hoffman MS, Roberts WS, et al. Externalized Groshong Catheters and Hickman Ports for Central Venous Access in Gynecologic Oncology Patients. Gynecologic Oncology. 1993 Dec;51(3):372–6.

DECEMBER 2020

Reviewer: Matthew R. Kappus, MD; As­­sistant Professor of Medicine, Division of Gastroenterology, Duke University, Durham, NC

Reference: Witjes J, Smits L, Pekmez C, Prodan A, et al. Donor Fecal Microbiota Transplantation Alters Gut Microbiota and Metabolites in Obese Individuals With Steatohepatitis. Hepatology Communications. 2020. Oct. doi/10.1002/hep4.1601

Why is this paper important? The microbiome plays an integral role in the gut-brain axis in patients with liver disease, and in particular nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Interestingly, NASH is significantly lower in individuals who prescribe to a plant-based, low-animal-protein diet, which is thought to be mediated by the gut microbiota. With the pandemic spread of obesity and type 2 diabetes, NASH has emerged as the most prevalent chronic liver disease worldwide1. The interaction between dietary changes and gut microbiota can potentially affect host physiology and pathophysiology2, and the results of this double-blind randomized controlled study further inform the landscape on how changes in the microbiota composition is associated with beneficial plasma metabolic profile and markers of steatohepatitis. 

Summary: This study is a single-center, double-blind, randomized controlled pilot study comparing the effect of three 8-weekly lean vegan donor fecal microbiota transplantation (FMT) versus autologous FMT on the severity of NAFLD, using liver biopsies in individuals with metabolic syndrome and hepatic steatosis on ultrasound. Individuals with hepatic steatosis on ultrasound were randomized to two study arms: lean vegan donor (allogenic n=10) or own (autologous n=11) FMT. Baseline characteristics and daily dietary intake, divided into four macronutrient and caloric content groups, did not significantly differ between the two groups. FMT was performed three times at 8-week intervals in both groups. A liver biopsy was performed at baseline and after 24 weeks in every subject to determine histopathology (Nonalcoholic Steatohepatitis Clinical Research Network) classification and changes in gene expression based on RNA sequencing. Secondary outcome parameters were changes in intestinal microbiota composition and fasting plasma metabolomics. There was observed trend in improvement in necro-inflammatory histology consisting of both lobular inflammation and hepatocellular ballooning after allogenic FMT. NAFLD activity score, steatosis, and fibrosis scores did not change over the period of 24 weeks in both groups. There were significant changes in expression of hepatic genes involved in inflammation and lipid metabolism following allogenic FMT. ARHGAP18 expression, a protective gene that maintains endothelial cell alignment, increased following allogenic FMT (P=0.002). Serine dehydratase (SDS) expression was significantly increased following allogenic FMT (P=0.049). In contrast, hepatic expression ofRECQL5 (P=0.014), a gene that is implicated in DNA double-strand break repair, and SF3B3 (P=0.004), a gene promoting cell proliferation and known to be an early stage driver in the development of liver cancer, increased in the autologous FMT group. Serologically there was improvement in GGT (P=0.038), ALT (P=0.099) in the allogenic FMT group. Fasting metabolites such as plasma phenyllactic acid, an adverse microbial product of aromatic amino acid metabolism, was increased following the autologous FMT (P=0.008).

At baseline, there was no difference in fecal microbiota alpha diversity (Shannon index) between individuals allocated to allogenic vs autologous FMT. Compared with autologous FMT, increases in fecal microbiota abundance following allogenic FMT were seen in beneficial bacteria related to Ruminococcus, Eubacterium hallii,Faecalibacterium, and Prevotella copri. There was only a minor shift in microbiota composition in the autologous FMT group, primarily associated with changes in abundance of Lachnospiracea

Commentary: The dysmetabolic syndrome is at a pandemic level and NAFLD has an estimated global prevalence of 25-30% and reaching staggering numbers in individuals with metabolic syndrome and type II diabetes mellitus1. Patients with NAFLD who progress towards NASH have a higher risk of developing hepatic cirrhosis, hepatocellular carcinoma, need for liver transplantation, and extrahepatic complications such as primary atherosclerotic cardiovascular disease. To date, the primary intervention is centered on dietary and lifestyle intervention along with co-morbid disease (hyperlipidemia, hypertension, diabetes mellitus, obstructive sleep apnea, etc) management. The impact of dietary changes on the gut microbiota is an attractive target in treatment of patients with dysmetabolic syndrome and NAFLD/NASH, as donor tissues in animal models following a healthy lifestyle can promote the similar phenotype in the recipient3,4. This ambitious research study is a feasibility study that was not powered for but did demonstrate a trend towards improvement in traditional histologic inflammatory scores between pre- and post-intervention liver biopsies. Additionally exciting, there were gene and metabolomic changes in the intervention group that demonstrate engraftment of the FMT which translated into metabolic impact. These results support previous studies that have examined the effect of FMT on NAFLD/NASH that improved intestinal permeability and insulin resistance5. This study demonstrates feasibility for future studies examining gut microbial manipulation in the treatment of NASH, and raises important considerations for delivery, FMT donor selection and recipient recruitment given the spectrum of disease from simple steatosis to steatohepatitis with fibrosis/cirrhosis. The prospect of transmitting microbiota resulting from healthy lifestyles to affect lasting metabolic benefit to patients with metabolic liver disease is an exciting concept that may not be too good to be true. This study validates previous studies on the relation between gut microbiota, and provides a framework for future microbiota-based intervention trials in patients with NAFLD and NASH. 

References:

  1. Younossi Z, Tacke F, Arrese M, et al. Global Perspectives on Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis. Hepatology 2019;69:2672-82.
  2. Johnson AJ, Zheng JJ, Kang JW, Saboe A, Knights D, Zivkovic AM. A Guide to Diet-Microbiome Study Design. Front Nutr 2020;7:79.
  3. Perez-Matute P, Iniguez M, de Toro M, Recio-Fernandez E, Oteo JA. Autologous fecal transplantation from a lean state potentiates caloric restriction effects on body weight and adiposity in obese mice. Sci Rep 2020;10:9388.
  4. Liu R, Kang JD, Sartor RB, et al. Neuroinflammation in Murine Cirrhosis Is Dependent on the Gut Microbiome and Is Attenuated by Fecal Transplant. Hepatology 2020;71:611-26.
  5. Craven L, Rahman A, Nair Parvathy S, et al. Allogenic Fecal Microbiota Transplantation in Patients With Nonalcoholic Fatty Liver Disease Improves Abnormal Small Intestinal Permeability: A Randomized Control Trial. Am J Gastroenterol 2020;115:1055-65.


NOVEMBER 2020

Reviewers: Vikram J. Christian MBBS, CNSC; Assistant Professor of Pediatrics, Division of Pediatric Gastroenterology, University of Minnesota, Minneapolis, MN

Reference: Bertoli S, Ramona, Bedogni G, Foppiani A, Leone A, Ravella S, Mastella C, Baranello G, Masson R, Bertini E, D'Amico A, Pedemonte M, Bruno C, Agosto C, Giaquinto E, Bassano M, Battezzati A. Predictive energy equations for spinal muscular atrophy type I children. The American Journal of Clinical Nutrition. 2020;111(5):983-996. doi:10.1093/ajcn/nqaa009

Why is this paper important? Management of nutrition in patients with Spinal Muscular Atrophy type I (SMAI) is challenging as there is limited knowledge on resting energy expenditure (REE) in this population. Both over- and under-nutrition are reported in children with SMA1,2. Moreover, there is known to be disproportion in fat-free mass, and fat mass in patients with SMAI, causing misinterpretation of nutritional status and difficulties in accurate determination of REE3. The recent introduction and FDA approval of Nusinersen has led to improved clinical outcomes. This improvement in outcomes and motor function is presumed to affect caloric requirements.

This study aims at addressing the significant knowledge gap in management of nutrition in patients with SMAI by proposing and validating predictive equations to estimate REE in children with SMAI. The authors take respiratory support requirements and Nusinersen therapy into consideration during analysis to further enhance the clinical relevance of the results.

Summary: A longitudinal observational study was conducted at the University of Milan. A total of 158 patients with a diagnosis of SMAI were enrolled. After excluding patients who were enrolled in ongoing clinical trials, those who had started treatment but did not complete the loading course of Nusinersen therapy, and those who did not reach steady state prior to indirect calorimetry, a total of 122 patients underwent measurement of REE by indirect calorimetry. Demographic, clinical, anthropometric, and treatment variables were obtained and analyzed to determine which factors best predicted measured REE. Parameters predicting REE were identified and linear regression models were used to develop predictive equations. The authors found that ventilated patients had a lower REE and Nusinersen therapy increased REE in both spontaneously breathing and mechanically ventilated patients. Predictive equations specific to respiratory support requirement and Nusinersen treatment were formed and validated.

Commentary: The authors are to be commended for addressing this significant knowledge gap. Predictive equations formulated by the authors take key factors such as respiratory support and Nusinersen therapy into consideration. Although these are pertinent considerations, the clinical relevance of these equations is limited. Further external validation may help in establishing the clinical applicability of these predictive equations. The work conducted by these authors will likely drive further research on the energy requirements of children with SMAI and ultimately the optimal nutrition support of these patients.

References:

  1. Poruk KE, Davis RH, Smart AL, et al. Observational study of caloric and nutrient intake, bone density, and body composition in infants and children with spinal muscular atrophy type I. Neuromuscul Disord. Nov 2012;22(11):966-73. doi:10.1016/j.nmd.2012.04.00
  2. Sproule DM, Montes J, Montgomery M, et al. Increased fat mass and high incidence of overweight despite low body mass index in patients with spinal muscular atrophy. Neuromuscul Disord. Jun 2009;19(6):391-6. doi:10.1016/j.nmd.2009.03.009
  3. Bertoli S, De Amicis R, Mastella C, et al. Spinal Muscular Atrophy, types I and II: What are the differences in body composition and resting energy expenditure? Clin Nutr. 12 2017;36(6):1674-1680. doi:10.1016/j.clnu.2016.10.020


OCTOBER 2020

Reviewers: Matthew L. Bechtold MD, FACP, FASGE, FACG, AGAF; Professor of Clinical Medicine; Division of Gastroenterology & Hepatology; University of Missouri, Columbia, MO
Sami Samiullah MD, FASGE, FACG; Assistant Professor of Clinical Medicine; Division of Gastroenterology & Hepatology; University of Missouri, Columbia, MO

Reference: Patel JJ, Kozeniecki M, Peppard WJ, Peppard SR, Zellner-Jones S, Graf J, Szabo A, Heyland DK. Phase 3 pilot randomized controlled trial comparing early trophic enteral nutrition with “no enteral nutrition” in mechanically ventilated patients with septic shock. JPEN J Parenter EnteralNutr. 2020 Jul;44(5):866-873. doi: 10.1002/jpen.1706.

Why is this paper important? Septic shock is common in intensive care units around the world. Septic shock manifests as severe hypotension unresponsive to intravenous fluids leading to the use of vasopressor agents. In these patients, splanchnic hypoperfusion has been feared given the decreased oxygen delivery and vasoconstriction by vasopressors. For the most part, these patients were given no enteral nutrition (EN) based on this idea of potential intestinal hypoperfusion despite EN improving immune and intestinal barrier function. This study is a step forward in helping patients with septic shock by evaluating the use of EN in this population that has long been denied.

Summary: This pilot study is a phase 3 randomized trial comparing early trophic EN to no EN in mechanically ventilated patients with septic shock on vasopressors. This study was performed on adult patients (≥ 18 years of age) at single center (Medical College of Wisconsin). In this study, septic shock was defined as an infected or presumed infected patient with persistent hypotension (mean arterial pressure < 70 mmHg) despite intravenous fluids requiring the use of a vasopressor. Exclusion criteria was basically a non-functioning gastrointestinal (GI) tract (recent GI surgery, small bowel ischemia/obstruction, severe vomiting) or inability/contraindication to place a feeding tube. In the early trophic EN group, patients were administered < 600 kcal/day while on vasopressor and increased to goal rate after being off vasopressor for at least 3 hours. In the no EN group, no EN was administered while on vasopressor and only initiated to goal rate after being off vasopressor for at least 3 hours. 15 patients received early EN and 16 received no EN. Patient demographics revealed early EN group was older and lower BMI than the no EN group. Compliance was outstanding in both arms (100% in early EN group vs 94% in no EN group). Contamination rate was also comparable between the two groups (0% vs 6%). Furthermore, early EN group had significantly more ICU-free days (median 25 vs 12 days) and ventilator-free days (median 27 vs 14 days) as compared to no EN group with no statistically significant difference in mortality (13% vs 33%).

Commentary: This a pilot study on a very interesting and pertinent subject. As far back as we can remember, it is extremely common and the norm to provide no EN to mechanically ventilated septic shock patients requiring vasopressor support. Given the benefits of trophic feeding in critically ill patients with many disease states (severe acute pancreatitis, burns, trauma, etc), it makes sense to study EN use in these patients. Prior studies have demonstrated varied results regarding feeding in patients on vasopressor support; however, feeding rates and patient populations differed. This study demonstrated that it is feasible to perform early trophic EN in this patient population with some encouraging results with ICU-free and ventilator-free days. However, this study did have some limitations. First, this study is not blinded to the physicians and research team. However, blinding would be difficult unless placebo gastric tube and solution with similar appearance of tube feeds were performed. Second, being a small pilot study, the statistical power was inadequate for assessing most clinical outcomes and complications. Therefore, the results of the study need to be interpreted with caution. Despite having a low statistical power, two outcomes did have statistically significance (ICU-free days and ventilator-free days) which is encouraging. Lastly, this is a pilot study and we require one or more larger RCTs for adequate comparison across all outcomes, including clinical parameters such as complications. Despite the limitations, this is very interesting study on early trophic EN in septic shock patients on vasopressor that deserves attention as this represents the initial attempt to define some evidence to guide our clinical practice. Again, just to be clear, the results of this small pilot study should not be over-interpreted. This study is the ground floor to further large-scale RCTs that will likely answer the question on feeding in these patients on vasopressor medications. We look forward to further work on this subject.


SEPTEMBER 2020

Reviewer: Senthilkumar Sankararaman, MD, FAAP, Pediatric Gastroenterologist & Physician Nutrition Specialist, Division of Pediatric Gastroenterology, Hepatology & Nutrition, UH Rainbow Babies & Children's Hospital; Assistant Professor, Case Western Reserve University School of Medicine, Cleveland, OH

Reference: Ledder O, Duvoisin G, Lekar M, et al. Early Feeding in Acute Pancreatitis in Children: A Randomized Controlled Trial. Pediatrics. 2020;146(3):e20201149

Why is this paper important? The traditional dogma of managing acute pancreatitis includes nil per os and intravenous fluids aimed to provide “rest” for the inflamed pancreas. However, many prior adult studies suggested that the converse is true, and early feeding is well tolerated and encouraged to minimize the pancreatitis-associated complications.(1, 2, 3)This recommendation is based on the fact that enteral feeding in acute pancreatitis may help preserve the mucosal integrity and motility of the intestinal tract, increase the splanchnic blood supply, and reduce the complications such as bacterial translocation.(4, 5) The latest guidelines from the European Society for Clinical Nutrition and Metabolism (ESPEN) on nutrition in pancreatitis recommends the early introduction of oral low-fat, soft diet as soon as possible in mild pancreatitis.(6) In patients with moderate to severe pancreatitis, early initiation (within 24-72 hours) of enteral nutrition via nasogastric or nasojejunal tube is recommended if oral feeding is not feasible or not tolerated.(6)

No prospective pediatric randomized controlled trial comparing the efficacy and safety of oral/enteral diet vs. no feeding in the early phase of acute pancreatitis exists. Most pediatric literature available on acute pancreatitis are either on retrospective studies or non-randomized, prospective data.(7,8,9) The recommendations from the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Cystic Fibrosis/Pancreas Working Group and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) Pancreas Committee were mostly extrapolations based on available adult literature and limited pediatric data.(10) Despite the recent recommendations encouraging early initiation of feeds, many pediatric clinicians still continue the traditional bowel rest with intravenous fluids.(10) Pancreatitis in children is frequently mild in nature and has diverse etiologies (such as biliary causes, medications, trauma, and various systemic disorders) whereas in adults, acute pancreatitis  is relatively more severe and most cases are secondary to alcohol ingestion, biliary diseases, and hypertriglyceridemia.(6,10) Hence prospective randomized feeding trials in children with acute pancreatitis are urgently needed. 

Summary: The authors reported a randomized controlled trial involving 33 children (2-18 years) with mild to moderate cases of acute pancreatitis. The study was carried out in 3 centers (Israel and Australia) between 2015-2018. Patients with severe pancreatitis were excluded. The authors also excluded pancreatitis due to biliary causes, severe trauma with pancreatic duct disruptions, autoimmune pancreatitis, and any underlying conditions which could restrict enteral feeding. Eligible patients were randomized either to immediate, full unrestricted diet (early feeding cohort) or initial fasting with intravenous fluids followed by a low-fat diet (initial fasting cohort). In the initial fasting cohort, the timing of institution of the low-fat diet was at the discretion of the treating physician upon symptom resolution. This approach is in line with the traditional way of management. In the early feeding cohort, unrestricted oral feeds were started as soon as the randomization was completed and the patient was ready for feeds. For patients unable to initiate oral feeds, enteral feeds using nasogastric tube or nasojejunal tube were recommended to start within 24 hours. As the focus of investigation is on the effect of early feeding on acute pancreatitis, the investigators excluded patients who presented >24 hours after the onset of symptoms. Pain scores, blood tests, and imaging were followed up in both groups. The cohort was slightly male preponderant (52% boys), and the mean age was 11.5 (+/-4.8) years. The groups were comparable in demographics, pain scores, and serum pancreatic enzyme levels at presentation. 18 (55%) were randomized to early feeding and 15 (45%) to initial fasting cohort. The median time (IQR) to initiate feeding in the early feeding group was 19.3 (10.9-26.8) hours vs. 34.7 (22-76.8) hours in the initial fasting group, P =.004. No patient in either group required exclusive nasogastric or nasojejunal feeds or parenteral nutrition. However, one child in the early feeding group did require partial nasogastric feeding supplementation initially.

The primary outcome was time to discharge and median time to discharge was not significantly different between the groups, 2.6 vs. 2.9 days. Secondary outcome variables included clinical and laboratory resolution of acute pancreatitis manifestations, and both local and systemic complications were minimal, and did not differ between the two groups. Patients were followed-up at 30-60 days after discharge. The early feeding group did have enhanced median weight gain (+1.3kg) vs. the initial fasting group who had significant weight loss (-0.8 kg), P =.028. 

Commentary: The authors have to be commended for conducting this first prospective randomized feeding trial in children with acute pancreatitis comparing early feeds vs. initial fasting in mild to moderate cases. While the findings are compelling, several limitations should be considered, including the small sample size. The sample size was calculated based on detecting a 30% reduction in hospital stay with a power of 80% and a significance level of 5% but not powered enough to detect the differences in complications between the groups. The study results may not be generalizable to all cases of acute pancreatitis in children as certain etiologies such as biliary and autoimmune pancreatitis were not included. Also, the authors did not elaborate about the etiology of the pancreatitis such as if they were drug-induced or secondary to systemic disorders and other etiologies. Even though the time of initiation of feeds between the two groups were significantly different, the median feeding initiation time in both groups was less than 48 hours, and most investigators consider this time period as initial acute phase of pancreatitis. As authors pointed out, this may be the reason why the study outcomes did not reach statistical significance between the groups.

Nevertheless, this study offers numerous important inferences such as the early initiation of diet is well tolerated and did not increase the hospital stay or complications from pancreatitis. This study also initiated plenty of intriguing questions to be answered on the optimal timing and route of feeding and predictors of feeding intolerance in children with acute pancreatitis. The significant weight discrepancies (~2 kg) between the groups initiates an interesting thought on benefits of early feeding in children and this finding is more apt for children who are malnourished or at risk of malnutrition. Even though the nutritional assessment and post-discharge diet intake were not detailed by the authors, the dietary fat intake differences (unrestricted fat vs. low-fat diet) could be one of the reasons for this weight discrepancy. Without a second thought, further larger, multicentered, prospective randomized controlled trials are needed to evaluate these encouraging findings. 

References:

  1. Vaughn VM, Shuster D, Rogers MA, Mann J, Conte ML, Saint S, Chopra V. Early versus delayed feeding in patients with acute pancreatitis: a systematic review. Annals of internal medicine. 2017;166(12):883-92.
  2. Horibe M, Nishizawa T, Suzuki H, Minami K, Yahagi N, Iwasaki E, Kanai T. Timing of oral refeeding in acute pancreatitis: a systematic review and meta-analysis. United European gastroenterology journal. 20164(6):725-32.
  3. Al-Omran M, Albalawi ZH, Tashkandi MF, Al-Ansary LA. Enteral versus parenteral nutrition for acute pancreatitis. CochraneDatabase Syst Rev. 2010;2010(1):CD002837. Published 2010 Jan 20. doi:10.1002/14651858.CD002837.pub2
  4. Wu LM, Sankaran SJ, Plank LD, Windsor JA, Petrov MS. Meta‐analysis of gut barrier dysfunction in patients with acute pancreatitis. British Journal of Surgery. 2014 ;101(13):1644-56.
  5. McClave SA, Heyland DK. The physiologic response and associated clinical benefits from provision of early enteral nutrition. Nutrition in Clinical Practice. 2009;24(3):305-15.
  6. Arvanitakis M, Ockenga J, Bezmarevic M, Gianotti L, Krznarić Ž, Lobo DN, Löser C, Madl C, Meier R, Phillips M, Rasmussen HH. ESPEN guideline on clinical nutrition in acute and chronic pancreatitis. Clinical Nutrition. 2020;39(3):612-31.
  7. Ellery KM, Kumar S, Crandall W, Gariepy C. The benefits of early oral nutrition in mild acute pancreatitis. The Journal of pediatrics. 2017;191:164-9.
  8. Abu-El-Haija M, Wilhelm R, Heinzman C, Siqueira BN, Zou Y, Fei L, Cole CR. Early enteral nutrition in children with acute pancreatitis. Journal of pediatric gastroenterology and nutrition. 2016;62(3):453-6.
  9. Szabo FK, Fei L, Cruz LA, Abu-El-Haija M. Early enteral nutrition and aggressive fluid resuscitation are associated with improved clinical outcomes in acute pancreatitis. The Journal of Pediatrics. 2015 Aug 1;167(2):397-402.
  10. Abu-El-Haija M, Uc A, Werlin SL, Freeman AJ, Georgieva M, Jojkić–Pavkov D, Kalnins D, Kochavi B, Koot BG, Van Biervliet S, Walkowiak J. Nutritional considerations in pediatric pancreatitis: A position paper from the NASPGHAN pancreas committee and ESPGHAN cystic fibrosis/pancreas working group. Journal of pediatric gastroenterology and nutrition. 2018;67(1):131.

AUGUST 2020

Reviewer: Michael C. Garcia, MD, Assistant Clinical Professor of Medicine, Division of Clinical Nutrition; University of California Los Angeles, Los Angeles, CA

Reference: Merker M, Felder M, Gueissaz L, et al. Association of baseline inflammation with effectiveness of nutritional support among patients with disease-related malnutrition: a secondary analysis of a randomized clinical trial. JAMA Netw Open. 2020;3(3):e200663. doi:10.1001/jamanetworkopen.2020.0663

Why is this paper important? Inflammation is associated with negative outcomes in medical inpatients, including longer hospital durations and increased mortality, and plays an important role in the pathogenesis of malnutrition. However, there is limited data evaluating the effect of inflammatory status on treatment response to nutritional support. This study demonstrates that inflammatory status influences individual response to nutritional support.

Summary: This study is a secondary analysis of the trial EFFORT and examined whether inflammatory status on admission using C-reactive protein (CRP) level was associated with the effect of nutritional support on all-cause mortality at 30 days, and if nutritional support was associated with CRP kinetics. Secondary end points included 180-day mortality, major complications, decline in functional status and hospital length of stay.

1950 patients, all at nutritional risk with Nutritional Risk Screening 2002 3, median age 75 years (65-83) and median BMI 24 were included in the analysis and stratified based on low (<10 mg/L), moderate (10-100 mg/L), and high (>100 mg/L) levels of inflammation using CRP. Infectious disease was the most common diagnosis, with a significantly higher percentage of these patients (60%) in the high inflammation group versus other diagnoses (cancer, cardiovascular disease, etc.). Per the initial trial EFFORT, patients in the nutritional support intervention group had higher mean calorie and protein intake, regardless of CRP value. Overall, the primary endpoint, 30-day mortality, was 7.0% in patients receiving nutritional support versus 9.7% in the control group, with adjusted OR of 0.61 (P=0.005). The benefit of nutritional support remained in those with low inflammation (adjusted OR, 0.34; P=0.02) and moderate inflammation (adjusted OR, 0.41; P=0.001). There was no benefit of nutritional support in patients with high inflammation (adjusted OR, 1.32; P=0.39). Effect modification was present for CRP on the association of nutritional support and mortality (P=0.005). Subgroup analysis of patients with infection suggested a similar association of nutritional support and 30-day mortality based on CRP group. No significant associations were found with secondary outcomes. Lastly, nutritional support was not found to be associated with CRP trend within the first 7-days of hospitalization.

Commentary: Both ESPEN and ASPEN guidelines recommend screening patients for malnutrition risk and implementing nutritional support in malnourished patients and those at nutritional risk. Earlier meta-analyses evaluating nutritional support in medical and mixed medical/surgical/critically ill patients did not find significant associations with mortality or other adverse outcomes. However, a more recent meta-analysis of nutritional support in malnourished or nutritionally at-risk medical inpatients showed improved survival.

The current study is a secondary analysis of EFFORT, a multicenter, randomized trial conducted in Swiss hospitals of non-critically ill medical inpatients at nutritional risk which demonstrated that individualized nutritional support initiated within 48-hours of admission (compared with standard hospital food) had a number of positive effects: reduced risk of composite adverse clinical outcomes (all-cause mortality, admission to ICU, non-elective hospital readmission after discharge, new major organ system complication) and all-cause mortality at 30 days; improvement in functional status and quality of life; no increase in potential side-effects from nutritional support. The secondary analysis in this study suggests patients with higher levels of inflammation at baseline/admission do not garner the mortality benefit of nutritional support seen in patients with low or moderate levels of inflammation, regardless of presence of infection as a primary diagnosis. There was no association of nutritional support on CRP trend during the initial 7 days of hospitalization. We know that inflammation has a number of metabolic and physiologic consequences, due to effects of cytokines on appetite/food intake, GI function, and insulin resistance, among other processes. These responses may be beneficial, especially in critically ill patients. In the non-critically ill patients in this study, those with high levels of inflammation do not respond as favorably to the addition of nutritional support, and this may even be harmful, though this was not specifically analyzed. It is possible that lower protein and calorie goals should be utilized in the presence of higher levels of inflammation; however, this should not be extrapolated until further studies are performed. 

There are several limitations to consider. The study used CRP levels alone to define level of inflammation. It would be beneficial to include additional markers of inflammation to evaluate their association with various degrees of malnutrition and nutritional support interventions in these scenarios. Additional analysis of level of inflammation in different diagnoses (apart from infection) and response to nutritional support would also be valuable. The initial trial was conducted in Swiss hospitals, thus the findings may not be applicable to all patient populations. This secondary analysis does not yield definitive results, but rather provides a foundation to conduct new studies more specifically focused on inflammation and its effects on inpatient nutritional support. In addition to mortality outcomes, other important measures to consider in future research include how inpatient nutritional support translates to the outpatient setting, and how patient-specific nutritional intervention may reduce readmissions and hospital utilization. Nonetheless, this study further emphasizes the importance of individualized nutritional prescriptions for inpatients, which should be tailored using baseline inflammation levels as an additional variable.


JULY 2020

Reviewer: Martin Daniel Rosenthal, MD Assistant Professor of Trauma, Acute Care Surgery, and Critical Care; Chair of UF Nutrition Committee, University of Florida, Gainesville, FL

References: Martinez et al. Effect of Preoperative Administration of Oral Arginine and Glutamine in Patients with Enterocutaneous Fistula Submitted to Definitive Surgery: a Prospective Randomized Trial.Journal of Gastrointestinal Surgery. 2020 Feb;24(2):426-434. doi: 10.1007/s11605-018-04099-4. Epub 2019 Feb 1. PMID: 30710211

What is the study question (in PICO format)? In Patients with enterocutaneous fistulas, does Intervention with immunonutrition, as Compared to standard treatment, improve the clinical Outcomes of fistula closure, inflammatory biomarkers, and reduce infectious complications?

Why is this study important? Treatment of enterocutaneous fistulas (ECF) and entero-atmospheric fistulas (EAF) remains complex as often times a ‘one size fits all’ approach does not apply to management strategies. Outside of the acute phase of fistula management where most experts agree on the classic principles of resuscitation, correction of electrolyte imbalances, source control of sepsis, skin protection, and metabolic support there is a diverse approach to ongoing treatment algorithms. Imbedded in the foundation of fistula management is nutritional support, but not all agree upon the how, what, why, and when of nutritional support. Countless discussion of parenteral nutrition versus enteral nutrition support have been had, but there is little to no recent randomized control trials guiding evidentiary based nutritional support. Since the late Stanely Dudrick gifted us parenteral nutrition (when we first saw a dramatic improvement in mortality) the literature has remained stagnant aside from large case series, most of them single center. This article  presented here, published in 2020, is noted for efforts in pushing ECF management forward, as well as, possibly birthing an ERAS model for those ECFs undergoing surgery.

Summary: From Jan 2011-2013 the authors performed a randomized single blinded study using a closed envelop randomization scheme to allocate 40 patients with ECF to 2 equal cohorts 1 week before undergoing surgical reversal.  The control cohort continued one with current nutritional support that they were previously on and the experimental arm received conventional treatment and additional 4.5g arginine coupled with 10g glutamine orally for seven days prior to surgery. The researchers determined that the patients needed at least 1 meter of functional small bowel prior to the fistula for absorption. Type and timing of the surgery was determined by the attending surgeon. Primary endpoint was ECF recurrence and secondary endpoints pertained to inflammatory biomarkers (IL-6, CRP) or infectious complications (pneumonia, UTI, central line infection, bacteremia).  

Of the 40 patients entered, 27 were male, median age was 54, 26 came were referred from outside hospitals, the origin was postoperative complications in all.  Interestingly, in this study colostomy takedown had the highest risk associated with fistula creation. Fistula was located in the jejunum (n=20), ileum (n=16), and colon (n=4). 30 patients had enteroatmospheric fistulas, which in 22 was a result of open abdomens from damage control operations. 25 patient were determined to be malnourished, while all patients could tolerate enteral nutrition to some varying degree as 29 patients still required some parenteral support for a median time of 139 days.  Surgery consisted of fistula resection and anastomosis (30 hand sewn and 10 stapled). Complete abdominal closure was feasible in 14 patients.  None of the demographic characteristics of the cohorts were statistically different, but trends towards significance was seen as the control group had more patients with ASA >3 and patients with multiple fistulas.  ECF recurrence occurred in 2 patients in the experimental group and nine patients admits the control (p <0.04).  Median time to recurrence was 6 days.  IL-6 and CRP had statistically significant lower serum concentration preoperative and post-operative days 1 (for IL-6), but not days 3 and 7 post-operative. Infectious morbidity was higher in the control group and not coincidentally all these patients had fistula recurrence.  

Commentary: The unfortunate aspect of fistula management is that there is scant contemporary level one evidence that drives clinical practice. This is impart secondary to ECFs relative low prevalence in society, but remains difficult generate high powered studies quickly. A well-executed prospective randomized control trial would take years at a single center, but perhaps a multicenter consortium of protocoloized fistula management could answer best practice questions for ECF management. Several significant questions that remain are not based on surgical technique but rather how to manage these patients in the time period between fistula emersion and operative reversal. Best practice for nutritional support remains highly debated even among ECF experts.    

In this manuscript Martinez and colleagues attempt to add amino acids as an oral supplement to enhance outcomes. Though not powered for specific clinical outcomes this trial has a flavor of Enhanced Recovery After Surgery (ERAS). Immunonutrition 1 week prior to surgery coupled with a 50g glucose load the morning of has been demonstrated to improve infectious and non-infectious complication, length of stay, insulin resistance, and even anastomotic leak rate.[1-6]  Most immune-nutrient formulas include arginine and omega 3 fatty acids, while some include leucine, glutamine, and nucleotides.[7-11]  The authors should be commended in their attempt to drive literature forward in determining best practice for ECF management, but I do have a few critiques. 

  1. No power analysis: it is essential to demonstrate a power analysis to strengthen clinical outcomes. Though there are little studies to derive such a power analysis on there exist well designed trials discussing clinical outcomes such as anastomotic leak in using immunonutrition preoperatively. Which at the end of the day what is a fistula reversal if not a GI anastomosis once the fistula is excised.
  2. Cohort mismatch: though none of the demographics were statistically different (p <0.05) there was a trend to the control group having multiple fistulas and were sicker based off ASA classification >3. The lack of statistical significance is likely related to low number of patients included in the trial.  Increased number of fistulas in the control group appears to naturally drive an increased number of anastomoses in the surgical outcomes that was required to reverse the fistulas.  Any time there is more anastomoses there is an inherent greater chance for leak.  More anastomoses coupled with half (n=10) the control group having an ASA >3 could skew primary outcomes of fistula recurrence before any intervention is even studied such as immunonutrition.
  3. Amino acid profile: in determining clinical relevance of an oral supplement I have always wondered if absorption factors into a potential confounder.  The authors rightfully enrolled only fistula patients with >1meter of bowel prior to the GI opening.  This should be plenty of length to absorb amino acids, but something as simple as an amino acid profile (inexpensive, quick test) could demonstrate that arginine and glutamine oral supplementation actually makes serum concentration improve.  Additionally, citrulline levels on the amino acid profile could serve as a rudimentary surrogate for GI absorption capacity. Lastly, most immunonutrition supplements for preoperative ERAS protocols also contain omega 3 fatty acids, which has proven to be beneficial in reducing inflammation. More as a question I am curious why fish oil wasn’t added to enhance recovery? 
  4. Criteria for parenteral: the authors make mention that “all patients were able to tolerate enteral diet while 29 patients (73%) received parenteral support. For a median of 139 days”. It would be interesting to see the percentage of support for these patients.  Was the patient on total parenteral nutrition despite being able to tolerate enteral diet? Was parenteral support used as supplemental parenteral nutrition? Was it added if there were signs of malabsorption and how did they determine that? To say that all patients tolerated enteral nutrition to me means they would be eating not ¾ of the study be on parenteral support. I do recognize supplemental parenteral support for those who cannot achieve caloric needs either through GI intolerance or malabsorption, but this was poorly discussed in the article.  
  5. Infectious morbidity: the authors begin their discussion with “the results of this study show that the preoperative use of oral arginine and glutamine in patients with ECF have positive effects in regard to fistula recurrence, postoperative inflammatory markers, and infectious complications”.  Additionally, the authors correctly mention that all infectious complications were in patients that had recurrence of their fistulas.  To make conclusions that the immunonutrients, arginine and glutamine, decreased post-operative infectious morbidity because all the infections occurred in the control group would be erroneous. I would submit that the infectious morbidity, and increased length of stay, in the control group was driven solely by the fistula recurrence requiring prolonged hospitalization and interventions. Again this could be in part reflected for the increased risk of anastomotic leak in the control group who had more fistulas and were sicker (ASA>3) at baseline.

Again the authors should be commended for studying a very difficult patient population, as the authors point out to us in their conclusions the tenets of fistula management remains the same for decades: “source control, appropriate management of sepsis, and nutritional support are key steps in the preoperative phase, and they need to be fulfilled before planning the operation itself”. I would add to their statement that correcting electrolyte imbalances and skin care are the complete foundation of fistula management, but there remains a nebulous middle ground that needs to be further explored.  After the acute phase (>2months) when the fistula is likely not going to spontaneously close there is a vast black hole of literature providing guidance for nutritional support. Most experts would agree that the non-caloric benefits of oral/enteral nutrition (even if it is oral food for comfort or trophic feeds) far outweigh parenteral nutrition[12, 13], but still fistula patients remain on parenteral support throughout their course awaiting surgical intervention without transitioning to or challenging the GI tract. The authors mentioned that all patients could tolerate diets and had bowel length >1m prior to the fistula, but the rationale for parenteral support was lacking (perhaps the patients couldn’t tolerate >60% of their goal calories). Nevertheless, at every turn in managing ECF we ought to be trying to get more and more enteral stimulation all the while checking for GI intolerance, malabsorption, dehydration, and other potential complications of intra-luminal nutrition. Nutritional support for fistulas should be dynamic and every attempt to de-escalate parenteral support should be made throughout the ‘middle ground’ management between fistula appearance and reversal.  Prior to reversal using studies like Martinez et al and Wang et al, there is no reason ECF surgical intervention shouldn’t follow most ERAS protocols using a week of immunonutrition to improve outcomes and shorten lengths of stay.  

References

  1. Marimuthu, K., et al., A meta-analysis of the effect ofcombinations of immune modulating nutrients on outcome in patients undergoingmajor open gastrointestinal surgery. Ann Surg, 2012. 255(6): p. 1060-8.
  2. Osland, E., et al., Effect of timing of pharmaconutrition (immunonutrition)administration on outcomes of elective surgery for gastrointestinalmalignancies: a systematic review and meta-analysis. JPEN J Parenter Enteral Nutr, 2014. 38(1): p. 53-69.
  3. Mazaki, T., Y. Ishii, and I. Murai, Immunoenhancing enteral and parenteralnutrition for gastrointestinal surgery: a multiple-treatments meta-analysis.Ann Surg, 2015. 261(4): p. 662-9.
  4. Amer, M.A., et al., Network meta-analysis of the effect ofpreoperative carbohydrate loading on recovery after elective surgery. Br J Surg, 2017. 104(3): p. 187-197.
  5. Bilku, D.K., et al., Role of preoperative carbohydrate loading: asystematic review. Ann R Coll Surg Engl, 2014. 96(1): p. 15-22.
  6. Smith, M.D., et al., Preoperative carbohydrate treatment forenhancing recovery after elective surgery. Cochrane Database Syst Rev, 2014(8): p. CD009161.
  7. Braga, M. and L. Gianotti, Preoperative immunonutrition: cost-benefitanalysis. JPEN J Parenter Enteral Nutr, 2005. 29(1 Suppl): p. S57-61.
  8. Braga, M., et al., Preoperative oral arginine and n-3 fattyacid supplementation improves the immunometabolic host response and outcomeafter colorectal resection for cancer. Surgery, 2002. 132(5): p. 805-14.
  9. Buzquurz, F., et al., Impact of oral preoperative andperioperative immunonutrition on postoperative infection and mortality inpatients undergoing cancer surgery: systematic review and meta-analysis withtrial sequential analysis. BJS Open, 2020.
  10. Cerantola, Y., et al., Immunonutrition in gastrointestinal surgery.Br J Surg, 2011. 98(1): p. 37-48.
  11. Gade, J., et al., The Effect of Preoperative Oral Immunonutrition on Complications andLength of Hospital Stay After Elective Surgery for Pancreatic Cancer--ARandomized Controlled Trial. Nutr Cancer, 2016. 68(2): p. 225-33.
  12. Kudsk, K.A., Effect of route and type of nutrition on intestine-derived inflammatoryresponses. Am J Surg, 2003. 185(1): p. 16-21.
  13. Kudsk, K.A., et al., Enteral feeding of a chemically defined dietpreserves pulmonary immunity but not intestinal immunity: the role oflymphotoxin beta receptor. JPEN J Parenter Enteral Nutr, 2007. 31(6): p. 477-81.

JUNE 2020

Reviewer: Manpreet Mundi, MD, Medical Director, Home Enteral Nutrition Program; Chair of Food Services; Chair of Outpatient Nutrition, Mayo Clinic, Rochester, MN

References: Martindale et al. Nutrition Therapy in the Patient with COVID-19 Disease Requiring ICU Care. Reviewed and Approved by the Society of Critical Care Medicine and the American Society for Parenteral and Enteral Nutrition, published online April 2020.

Barazzoni, Rocco, Stephan C. Bischoff, Zeljko Krznaric, Matthias Pirlich, and Pierre Singer. ESPEN Expert Statements and Practical Guidance for Nutritional Management of Individuals with Sars-Cov-2 Infection. Clinical Nutrition, March 2020. https://doi.org/10.1016/j.clnu.2020.03.022.

Commentary: As of May 11, there have been over 4 million confirmed cases of COVID-19 and over 280,000 deaths worldwide. The United States alone is fast approaching 80,000 deaths. Despite social distancing, which has flattened the case rate and mortality curves, the end of the pandemic is not yet in sight. Like other frontline healthcare workers, the nutrition community must be prepared and remain dynamic to manage patients in the new landscape that has been created by the COVID-19 pandemic.

Approximately 5% of those who contract the SARS-CoV-2 virus require critical care services, often related to respiratory failure requiring prolonged endotracheal intubation. In the absence of definitive therapy for COVID-19, good supportive care remains the cornerstone of caring for critically ill COVID-19 patients. Nutrition support is an essential component of good supportive care. In a recent article published jointly by the Society of Critical Care Medicine and the American Society for Parenteral and Enteral Nutrition, Martindale and colleagues provide recommendations relating to nutritional support for critically ill patients with COVID-19. Their recommendations are rooted in key guiding principles that are relevant to COVID-19, including limiting patient exposure and protecting healthcare workers by ‘clustering’ care, following CDC and WHO guidelines for utilizing personal protective equipment (PPE), and preserving PPE. They outline 12 key recommendations and highlight that the timing of nutrition support is one of the most important issues. They recommend enteral nutrition be initiated within 24-36 hours of intensive care unit (ICU) admission in a patient unable to maintain volitional oral intake. The authors point out some unique circumstances related to COVID-19, including gastrointestinal symptoms (related to COVID-19), circulatory shock, and characteristics of the affected, such as older age, anorexia, and pre-existing co-morbidities. These patient and disease characteristics lead to a greater risk for enteral feeding intolerance. Consequently, the authors underscore the recommendation for early transition to parenteral nutrition (PN) when gastric feeding is not tolerated. This recommendation is anchored on the key guiding principle of limiting patient-healthcare provider interactions since insertion of a naso-jejunal tube places healthcare staff at higher risk of direct exposure to the SARS-CoV-2 virus. Next, authors recommend that enteral feeds be started slowly and advanced to an energy goal of 15-20 kcal/kg (70-80% of caloric requirements) and protein goal of 1.2-2.0 g/kg/day. For PN, conservative dextrose and volume should be used early in the disease and slowly advanced as tolerated. Other key COVID-19 relevant recommendations include not checking gastric residual volumes and, based on safety data, starting early EN in patients undergoing extracorporeal membrane oxygenation and prone positioning, both of which are modalities used in COVID-19 related refractory hypoxemic respiratory failure.

Similar to hospitalized patients, the “clustering” approach should also be followed with outpatient nutrition support. Nutrition support providers should make every effort to conduct as much care as possible through telehealth in order to prevent unnecessary exposure. Routine laboratory studies, if they cannot be deferred, should be conducted at the patient’s home or local facility. Additionally, providers should be aware that patients with SARS-CoV-2 infection may present with nonspecific symptoms such as respiratory changes, fever, and GI deterioration. Thus, given the high prevalence of COVID-19, nutrition patients reporting these symptoms should be assessed for both SARS-CoV-2 infection and other nutrition related complications such as central line associated bloodstream infections.

The COVID-19 pandemic has limited family and medical access to patients and has created resource shortages. The nutrition community, as an essential front-line service, has been called upon to create new guidelines in order to optimize patient outcomes and protect health care staff. In addition to implementing key recommendations outlined in recent publications, we must also appreciate the emotional toll of the pandemic and use compassion and a non-judgmental approach with our patients and colleagues in order to support each other through the challenges with which we are now faced.

 


MAY 2020

Reviewer: Manpreet Mundi, MD, Endocrinologist, Internist, Mayo Clinic

References: Martindale et al. Nutrition Therapy in the Patient with COVID-19 Disease Requiring ICU Care. Reviewed and Approved by the Society of Critical Care Medicine and the American Society for Parenteral and Enteral Nutrition, published online April 2020.

Barazzoni, Rocco, Stephan C. Bischoff, Zeljko Krznaric, Matthias Pirlich, and Pierre Singer. ESPEN Expert Statements and Practical Guidance for Nutritional Management of Individuals with Sars-Cov-2 Infection. Clinical Nutrition, March 2020. https://doi.org/10.1016/j.clnu.2020.03.022.

Commentary: As of May 11, there have been over 4 million confirmed cases of COVID-19 and over 280,000 deaths worldwide. The United States alone is fast approaching 80,000 deaths. Despite social distancing, which has flattened the case rate and mortality curves, the end of the pandemic is not yet in sight. Like other frontline healthcare workers, the nutrition community must be prepared and remain dynamic to manage patients in the new landscape that has been created by the COVID-19 pandemic.

Approximately 5% of those who contract the SARS-CoV-2 virus require critical care services, often related to respiratory failure requiring prolonged endotracheal intubation. In the absence of definitive therapy for COVID-19, good supportive care remains the cornerstone of caring for critically ill COVID-19 patients. Nutrition support is an essential component of good supportive care. In a recent article published jointly by the Society of Critical Care Medicine and the American Society for Parenteral and Enteral Nutrition, Martindale and colleagues provide recommendations relating to nutritional support for critically ill patients with COVID-19. Their recommendations are rooted in key guiding principles that are relevant to COVID-19, including limiting patient exposure and protecting healthcare workers by ‘clustering’ care, following CDC and WHO guidelines for utilizing personal protective equipment (PPE), and preserving PPE. They outline 12 key recommendations and highlight that the timing of nutrition support is one of the most important issues. They recommend enteral nutrition be initiated within 24-36 hours of intensive care unit (ICU) admission in a patient unable to maintain volitional oral intake. The authors point out some unique circumstances related to COVID-19, including gastrointestinal symptoms (related to COVID-19), circulatory shock, and characteristics of the affected, such as older age, anorexia, and pre-existing co-morbidities. These patient and disease characteristics lead to a greater risk for enteral feeding intolerance. Consequently, the authors underscore the recommendation for early transition to parenteral nutrition (PN) when gastric feeding is not tolerated. This recommendation is anchored on the key guiding principle of limiting patient-healthcare provider interactions since insertion of a naso-jejunal tube places healthcare staff at higher risk of direct exposure to the SARS-CoV-2 virus. Next, authors recommend that enteral feeds be started slowly and advanced to an energy goal of 15-20 kcal/kg (70-80% of caloric requirements) and protein goal of 1.2-2.0 g/kg/day. For PN, conservative dextrose and volume should be used early in the disease and slowly advanced as tolerated. Other key COVID-19 relevant recommendations include not checking gastric residual volumes and, based on safety data, starting early EN in patients undergoing extracorporeal membrane oxygenation and prone positioning, both of which are modalities used in COVID-19 related refractory hypoxemic respiratory failure.

Similar to hospitalized patients, the “clustering” approach should also be followed with outpatient nutrition support. Nutrition support providers should make every effort to conduct as much care as possible through telehealth in order to prevent unnecessary exposure. Routine laboratory studies, if they cannot be deferred, should be conducted at the patient’s home or local facility. Additionally, providers should be aware that patients with SARS-CoV-2 infection may present with nonspecific symptoms such as respiratory changes, fever, and GI deterioration. Thus, given the high prevalence of COVID-19, nutrition patients reporting these symptoms should be assessed for both SARS-CoV-2 infection and other nutrition related complications such as central line associated bloodstream infections.

The COVID-19 pandemic has limited family and medical access to patients and has created resource shortages. The nutrition community, as an essential front-line service, has been called upon to create new guidelines in order to optimize patient outcomes and protect health care staff. In addition to implementing key recommendations outlined in recent publications, we must also appreciate the emotional toll of the pandemic and use compassion and a non-judgmental approach with our patients and colleagues in order to support each other through the challenges with which we are now faced.

 


APRIL 2020

Reviewer: John K. DiBaise, MD, Professor of Medicine, Division of Gastroenterology, Mayo Clinic in Arizona

Reference: Molina-Infante J, Arias A, Alcedo J, et al. Step-up empiric elimination diet for pediatric and adult eosinophilic esophagitis: The 2-4-6 study. J Allergy Clin Immun 2018;141:1365-1372.

Whyis this paper important? Numerous dietary restrictions and endoscopies limit the implementation of empiric elimination diets in patients with eosinophilic esophagitis (EoE). This paper provides supporting evidence for a step-up diet elimination approach that results in early identification of a majority of responders to an empiric diet with few food triggers, avoiding unnecessary dietary restrictions, reducing endoscopies and shortening the diagnostic process.

Summary: This was a prospective multicenter study conducted in adult (106) and pediatric (25) patients who underwent a 6-week 2-food-group elimination diet (TFGED; milk and gluten-containing cereals). Clinicopathologic response was defined by symptom improvement and less than 15 eosinophils/high-power field on esophageal biopsy. Nonresponders were offered a 4-food-group elimination diet (FFGED; TFGED plus egg and legumes) and then a 6-food-group elimination diet (SFGED; FFGED plus nuts and fish/seafood). In responders, eliminated food groups were reintroduced individually, followed by endoscopy. Ninety-seven patients completed all phases of the study. A TFGED achieved EoE remission in 56 (43%) patients, with no differences between children and adults. Food triggers in TFGED responders were milk (52%), gluten-containing grains (16%), and both (28%). Per-protocol remission rates with FFGEDs and SFGEDs were 60% and 79%, with increasing food triggers. Overall, 55 (91.6%) of 60 of the TFGED/FFGED responders had 1 or 2 food triggers. Compared with the initial SFGED, a step-up strategy reduced endoscopies and diagnostic evaluation time by 20%.

Commentary: Eosinophilic esophagitis is a chronic immune-mediated disease characterized most commonly by dysphagia with or without recurrent esophageal food bolus impaction and eosinophil-predominant mucosal inflammation histologically. EoE, now the leading cause of dysphagia among children and adults in Western countries, has been demonstrated to be a distinct form of food allergy (non-IgE, delayed, cell-mediated hypersensitivity). Unlike pharmacologic therapies such as proton pump inhibitors and topical/systemic corticosteroids that target the inflammatory consequences, diet therapy targets the cause of the disease. While effective, an elemental diet has not gained widespread use, and use of food allergy testing-guided diet elimination has not yielded good clinical outcomes. The standard elimination diet used in EoE since 2006 is the SFGED. Currently, food groups to be avoided long-term can only be identified by individual food reintroduction followed by endoscopic histologic reevaluation. Despite the reproducible effectiveness of this strategy, because of the large number of endoscopies/biopsies required to document histologic response after serial food reintroduction, its use in clinical practice has been limited. Importantly, it has been found that nearly three-quarters of responders to a SFGED have just 1 or 2 food triggers, most commonly cow’s milk, wheat, egg and soy/legumes. This led to the development of the FFGED. Because cow’s milk and gluten-containing grains are the most common food triggers in reports to date, Molina-Infante et al. aimed to start with the TFGED and gradually step up to a FFGED and eventually to a SFGED in nonresponders in order to determine both the effectiveness and resource-savings of this approach. This was the first multicenter, prospective study investigating the step-up dietary approach. Strengths of the study include the large sample size, the systematic approach, and the inclusion of both children and adults. Limitations are lack of a control group, the nearly 30% drop-out rate which undoubtedly leads to an overestimation of the success rate of the diet, lack of measuring compliance with diet recommendations, and uncertain generalizability of the results to other geographical areas with different food consumption habits.


MARCH 2020

Reviewer: Berkeley N. Limketkai, MD, PhD; Associate Clinical Professor of Medicine, Division of Digestive Diseases; University of California Los Angeles, Los Angeles, CA

Reference: Levine A, Rhodes JM, Lindsay JO, et al. Dietary Guidance for Patients with Inflammatory Bowel Disease from the International Organization for the Study of Inflammatory Bowel Disease. Clin Gastroenterol Hepatol. Feb 2020. doi: 10.1016/j.cgh.2020.01.046

Why is this paper important? In the absence of clear data about solid foods beneficial for inflammatory bowel diseases (IBD), patients are often faced with the need to explore and experiment with tenuous recommendations about foods prudent to consume or avoid. This endeavor is further complicated by the myriad and often conflicting sources of information available in the clinic, in print, and online. This study comprises a systematic effort by the International Organization of Inflammatory Bowel Diseases (IOIBD) to evaluate existing data and provide consensus-based recommendations on different food components for patients with IBD.

Summary: The 12-member IOIBD Nutrition Cluster evaluated the research data on 7 food groups and 5 food additives related to their effects on intestinal inflammation. Where human data were sparse, more emphasis was placed on animal data. Recommendations were made based on consensus in group discussion and provided in 4 categories: prudent to increase consumption, prudent to decrease or avoid consumption, safe to consume, or insufficient evidence to make a claim. The level of evidence was classified as “high” for randomized controlled trials (RCTs), “low” for observational human studies, and “very low” otherwise. In brief, the IOIBD suggested moderate-to-high consumption of fruits and vegetables (low evidence) for Crohn’s disease (CD), except in the presence of significant fibrostricturing disease. There was however insufficient evidence to make any recommendations about fruit and vegetable consumption for ulcerative colitis (UC). High-level evidence indicated that restriction of moderate amounts of unprocessed red meats, lean chicken meat, and eggs is unnecessary for CD; reduction of red and processed meat was advised for UC (low evidence). There were recommendations to reduce saturated fats (low evidence) and avoid trans fats (very low evidence) for CD and to reduce myristic acid (low evidence) for UC. Increased consumption of omega-3 fatty acids from fish (low evidence) but not supplements (high evidence) and avoidance of trans fat (very low evidence) was also advised for UC. The group recommended limited intake of maltodextrin-containing foods, artificial sweeteners, emulsifiers, thickeners, and processed foods containing titanium dioxide and sulfites for both CD and UC (very low evidence). Consensus was not obtained for pasteurized dairy products. There was no evidence of unpasteurized dairy products, but the group advised against its consumption. There was insufficient evidence to make any recommendations regarding consumption of refined carbohydrates, wheat, gluten, alcohol, 

Commentary: The study presents a systematic attempt at assessing the current state of evidence for various food groups to allow clinicians and patients to understand beneficial and detrimental foods for IBD. Notably, the quality of evidence was predominantly either low, very low, or insufficient; these disappointing findings illustrate the key challenges and underlying reasons for much confusion about dietary recommendations. Even fruits and vegetables, which would be highly suspected to provide anti-inflammatory effects in UC, were noted to have insufficient evidence to make a recommendation. On the other hand, despite the low quality of evidence available, patients cannot await RCTs to be performed for each food group prior to deciding on their next meal. Dietary recommendations for IBD are thus a dynamic process, integrating available data and acting on hypotheses on how certain foods may interact with the gastrointestinal system. This is also a call for more funding and research to further clarify our evolving understanding on this topic.


FEBRUARY 2020

Reviewer: Jeffrey I. Mechanick, M.D., Professor of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY

Reference: Deelen J. A metabolic profile of all-cause mortality risk identified in an observational study of 44,168 individuals. Nat Communic 2019; 10:3346; https://doi.org/10.1038/s41467-019-11311-9.

Why is this paper important? Nutrition refers to the intersection of dietary factors and metabolism in the context of disease prevention, disease management, and health promotion. Within this framework, a new, accurate model to predict 5- and 10-year mortality is presented based on metabolomics, where each of the 14 biomarkers has a nutritional implication.

Summary: This is a large metabolomics study of 44,168 individuals from 12 different cohorts, spanning a wide age range (18-109), and where there were 5,512 deaths during follow-up. Using a high-throughput, well-standardized nuclear magnetic resonance platform, and a stepwise (forward-backward) analytic procedure based on meta-analysis results, 14 metabolic biomarkers were identified that when combined into a biomarker score, were highly associated with, and accurately predicted all-cause mortality, for men and women and across all ages:   

  1. total lipids in chylomicrons and extremely large VLDLs;
  2. total lipids in small HDLs;
  3. mean diameter of VLDLs;
  4. ratio of polyunsaturated to total fatty acids;
  5. glucose;
  6. lactate;
  7. 5 amino acids – histidine, isoleucine, leucine, valine, and phenylalanine;
  8. acetoacetate;
  9. albumin; and
  10. glycoprotein acetyls.

The precision accuracy for this new model exceeded that previously described using conventional risk factors.

Commentary: There are several important take-away messages from this study. First, this predictive model represents an improvement over previous models due to (1) a larger number of individuals, from a diverse and numerous set of well-established cohorts, with a relatively large number of deaths with follow-up and (2) a revised premise that intermediate- and long-term predictions are complicated, especially in older individuals who typically have multiple and interacting chronic diseases, prompting study of more proximal drivers for health/wellness (e.g., immunity, inflammation, metabolism, and nutrition), instead of distal drivers for specific disease (e.g., diabetes and cardiovascular disease). Second, that the successful implementation of predictive models, using relatively inexpensive biomarker platforms as in this study, to identify patients at higher risk for mortality can trigger early case finding and preventive care for a sustainable effect. Third, the role of nutrition in the crux of this predictive model emphasizes the central role of nutritional medicine in early, preventive strategies and tactics.


JANUARY 2020

Reviewer: Ryan T. Hurt, MD, PhD; Professor of Medicine, Division of General Internal Medicine, Mayo Clinic, Rochester, MN

Reference: Reignier J et al Enteral versus parenteral early nutrition in ventilated adults with shock: a randomized, controlled, multicentre, open-label, parallel-group study (NUTRIREA-2). Lancet. 2018; 391: 133-143. 

Why is this paper important? The optimal route and timing of nutrition support has been shown to impact clinical outcomes in the intensive care unit (ICU). NUTRIREA-2 follows the large randomized controlled trial (RCT) CALORIES from England comparing 28 day mortality enteral nutrition (EN) and parenteral nutrition (PN) in ventilated ICU patients. NUTRIREA-2 enrolled participants who were receiving a vasoactive agent within 24 hours of intubation to study the effects of route of nutrition on mortality in this group of patients. Many clinicians have concerns about starting early nutrition in this patient population.  

Summary: The large (n=2400) English RCT (CALORIES) of ICU patients provided strong evidence that the there was no difference in early EN and PN outcomes such as infection. The French NUTRIREA-2 trial was designed to examine those who specifically who were on vasoactive agents in addition to being ventilated. Not all of the CALORIES trial participants required vasoactive agents. The NUTRIREA-2 authors hypothesized that outcomes in early EN would be improved compared to early PN. The primary aim of the study was mortality at study day 28.  The study design was a multicenter, open-label (blinding for EN and PN was deemed possible), parallel-group, RCT conducted in 44 French ICUs. To be included in the trial the participants had to be >18 years old, mechanically ventilated, receiving a vasoactive agent for shock, and be able to start early EN or PN within 24 hours of onset of critical illness (defined as when the patient was intubated). Those meeting inclusion criteria were randomly assigned (n=2410; EN=1202, PN= 1208) in a 1:1 fashion to either PN or EN within 24 hours after intubation. The target calorie range for both EN and PN was 20–25 kcal/kg per day. Participants that were randomized to PN could be transitioned to EN after 72 hours of PN if there was resolution of the shock and they were off vasopressors for > 24 hours. Participants in the PN group received more calories over the entire study period compared to the EN group (EN=17.8 kcal/kg/d vs PN= 19.6 kcal/kg/d PN; p <0.0001). In addition PN participants received more protein (EN= 0.7 g/kg/d vs PN= 0.8 g/kg/d; p<0.0001). There was no significant difference in the primary outcome according to feeding route.  At day 28 the PN group had 422 participants (422/1208= 34.9%) and the EN group had 443 (443/1202=36.9%) that died. There were no significant differences in the secondary outcome of ICU acquired infections (PN =194; EN= 173). The secondary outcomes associated with GI tolerance all favored PN. These included incidence of vomiting (PN= 246, 20% vs EN= 406, 34%; HR 1.89 [1.62–2.20]; p<0·0001), diarrhea (PN= 393, 33% vs EN = 432, 36%; HR 1.20 [1.05–1.37]; p=0·009), acute colonic pseudo-obstruction (PN= 3, <1% vs 11, 1%; HR 3.7 [1.03-13.2; p =0.04), and bowel ischemia (PN=5, <1% vs EN= 19, 2%; HR 3.84 [1.43-10.3] p=0.007. Greater than twice as many hypoglycemic events were reported in the EN group (EN=29/1202 vs PN= 13/1208; p=0.006). Based on these results the authors stated conclusion was in ICU patients with shock requiring vasoactive agents early isocaloric EN did not reduce mortality or infections compared to PN. They did note that early EN was associated with risk of GI complications when compared to early PN.              

Commentary: The NUTRIREA-2 trial is the second recent large RCT demonstrating that early EN did not improve ICU outcomes such as mortality or infections. Although early PN did have improved outcomes such as diarrhea, bowel obstruction, and hypoglycemia these did not lead to improvements such as ICU length of stay or duration of mechanical ventilation.  One of the reasons that clinicians hesitate to place patients who require vasopressor support in the ICU on early enteral nutrition is the fear of intestinal ischemia. NUTRIREA-2 did demonstrate that those placed on early enteral nutrition did have a higher incidence of bowel ischemia compared to those randomized to parental nutrition.  One of the things to highlight from a practical clinical purpose is that NUTRIREA-2 was aggressive in early feeding with goal calories set at 20-25 kcals/kg/day.  There is an emerging set of data that suggest early hypocaloric (as it pertains to the goal calories) feeding strategies may have lower rates of gastrointestinal complications especially in the situation of continued vasoactive support following resuscitation from shock.  In the 2 years since the publication of NUTRIREA-2 it has raised as many questions as it has answered. 

Should PN be used instead of EN early inICU patient requiring vasoactive support? Besides the gastrointestinal complications there was no significant difference in mortality, infection, length of stay in the ICU, or ventilator time.  As mentioned above the better question is should we be aggressively feeding this patient population within 24 hours of ventilation by either route.  There are number of other considerations to be made as well including the non- nutritional benefits of enteral nutrition over parental nutrition as well as the increased cost of PN verses EN.  Based on this most nutritional guidelines and society will likely conclude that EN should still be the preferred route once it is determined the patient is safe to be fed.

If my patient cannot tolerate EN due togastrointestinal complications in ICU can I consider PN? The ASPEN 2016 critical care guidelines did not have either the CALORIES or NUTRIREA-2 trial included as part of it is analysis and thus recommendations.  It does seem reasonable that if early nutrition is needed in situations (such as malnutrition prior to intubation) and patients are unable to tolerate EN that PN could be considered.  We have improved the safe delivery of parenteral nutrition over the past 30 years which have included better care of central venous catheters and being mindful of not over feeding.  Probably the biggest take home point from both CALORIES and NUTRIREA-2 is that PN delivery in the ICU has improved and clinicians should consider it a more safe and viable option.           


DECEMBER 2019

Reviewer: Sara Bonnes, MD, MS, Assistant Professor of Medicine, Mayo Clinic, Rochester, MN 

Reference: Francis HM, Stevenson RJ, Chambers JR, Gupta D, Newey B, Lim CK (2019) A brief diet intervention can reduce symptoms of depression in young adults – A randomised controlled trial. PLoS ONE 14(10): e0222768. 

Why is this paper important? Lifestyle interventions and improving diet quality are associated with weight loss and reduced risk of mortality; however we may not consider or discuss with patients the other benefits. This study showed that improving dietary patterns was associated with a reduction in symptoms of depressed mood. 

Summary: This study included 76 individuals enrolled in tertiary education in Australia and New Zealand between ages 17-35 recruited through a psychology course or flyers elsewhere on campus that demonstrated evidence of depressive symptoms based on Depression Anxiety and Stress Scale– 21 depression subscale (DASS-21-D)>7 and evidence of poor diet as defined by a score >57 on the Dietary

Fat and Sugar Screener (DFS).  Participants were randomized into a control group that received no diet instruction and an intervention group that received instruction on a healthy diet via a 13 minute video created by a registered dietitian that followed the recommendations of the Australian Guide for Healthy Eating and emphasized the importance of omega 3 fatty acids, increasing consumption of fruits, vegetables and whole grains and also consuming regular amounts of cinnamon and turmeric while decreasing consumption of refined carbohydrates, fatty or processed meats and soft drinks.  Dietary compliance in the intervention group was assessed via questionnaire and there was phone call follow up on Days 7 and 14. The intervention group also received a gift card to help offset the cost of these foods and a small gift basket containing some of these food items. DASS-21 was reassessed on day 21 and the group undergoing dietary intervention had significantly lower DASS-21 scores as compared to the beginning of the study and compared to the control group, where scores were stable from the beginning of the study.  DASS scores for anxiety and stress also significantly improved. There was no significant change in measures for memory or other mood assessment tools. They did try 3 month phone follow up and were able to reach 33 participants. Those in the dietary intervention group did still have significant improvement in mood. Reduction in processed foods was most strongly correlated with the decrease in depressive scores. 

Commentary: While this is a small study with short term follow up, it is among the limited randomized controlled trials looking at dietary interventions and depressive symptoms. Certainly for many patients with depressive symptoms, psychotherapy and pharmacotherapy will be important aspects of treatment, but as we are working with patients, it is important to consider the other potential benefits of working to improve diet quality. It is also important for us to consider the impact of diet on mood in patients who are transitioning from oral intake to enteral or parenteral nutrition. Significant health changes can certainly impact mood and outlook, but potentially nutrient intake may also impact mood. As patients are undergoing significant life changes, we should assess the impact and mood and consider a multi-faceted approach to address these issues.      


NOVEMBER 2019

Reviewer: Carolyn Newberry, MD; Assistant Professor of Medicine, Division of Gastroenterology, Weill Cornell Medical Center, New York, NY

Reference: Sotos-Prieto, M, Bhupathiraju SN, Mattei J et al. Association of Changes in Diet Quality with Total and Cause-Specific Mortality. NEJM. 2017 July 13. Doi:10.1056/NEJMosa1613502. 

Why is this paper important? This large observational cohort study associates improved diet quality (as defined by the Alternate Healthy Eating Index-2010 (AHEI), Alternate Mediterranean Diet Score (AMD), and the Dietary Approaches to Stop Hypertension (DASH) Diet Score) with reduction in all-cause mortality.  

Summary: This paper is a large observational cohort study that analyzes two commonly examined databases, the Nurses’ Health Study, a prospective study started in 1976 including 121,700 registered nurses between the ages of 30 and 55 years, and the Health Professionals Follow-Up Study, a prospective study initiated in 1986 enrolling 51,529 US Health Professional between the ages of 40 and 75 years. The study examines dietary quality over a 12 year period (1986-1998). Patients were excluded if they had history of cancer or cardiovascular disease at or before the baseline set in 1998, missing information regarding diet and lifestyle covariates, or very high calorie (>4200kcal/day in men or 3500kcal/day in women) or very low calorie (<800kcal/day in men, <500kcal/day in women) intake. In total, 47,994 women and 25,745 men were analyzed. Dietary assessment was performed at baseline and every 4 years thereafter utilizing a validated food frequency questionnaire. The three diet-quality scores were then calculated based on previously published standardized measures. These diet quality scores assess intake of fruits, vegetables, whole grains, nuts, legumes, and long chain n-3 fatty acids in comparison to sugar-sweetened beverages, fruit juices, red and processed meats, trans-fat, saturated to unsaturated fat ratios, sodium, and alcohol. Deaths were tabulated using national databases and reports by family and post office records. Information regarding lifestyle and risk factors for cardiovascular disease were evaluated and updated annually including: age, weight, smoking status, use of aspirin, multi-vitamins, post-menopausal status, physical activity, hypertension, hypercholesterolemia, diabetes. Statistical modeling assessed association between the three diet-quality scores and date of death or the end of follow up, whichever came first. Cox proportional-hazards models were used to establish hazard ratios and 95% confidence intervals with additional analysis to correct for confounding variables and confirm robustness of correlation.  The pooled hazard ratios for all-cause mortality among participants who had the greatest improvement in diet quality (13-33% improvement) as compared to stable diet quality (0-3% improvement) were: 0.91 (95% CI: 0.85-0.97) according to the AHEI, 0.84 (95% CI 0.78-0.91) according to the AMD Score, and 0.89 (95% CI 0.84-0.95) according to the DASH Score. Among participants who maintained high quality diet as compared to a low quality diet, risk of death by any cause was significantly lower—14% (95% CI 8-19) by AHEI, 11% (95% CI 5-18) by AMD Score, and 9% (CI 2-15) by DASH Score. 

Commentary: Considering the increased prevalence of western dietary practices, which are characterized by inadequate fruit, vegetable, and whole grain intake in favor of highly processed foods containing large amounts of saturated fats and simple carbohydrates, the association between diet quality and overall mortality becomes increasingly important. This paper highlights the reduction in mortality from any cause in association with both improvement in diet quality over time as well as maintenance of a healthy diet. Quality is defined by common scoring systems, which are easy to use and can be incorporated into both clinical practice and patient education tools. Although slight variations exist between these dietary models, overall themes emerge including increased intake of whole grains, vegetables, fruits, and n-3 fatty acid sources such as fish with concomitant reduction in processed meats, sugars, and excessive sodium intake. The current 2015-2020 Dietary Guidelines Advisory Committee mirrors such recommendations, confirming the components of healthy eating patterns as described and a recommendation to support Americans in shifting eating patterns. This national guidelines committee will meet once again in 2020 where it is poised to analyze personal, family, societal, and governmental changes that need to be addressed in order to enable such transformations. The goal is to promote a new paradigm in healthy lifestyle choices that provides accessible and affordable options at home, school, work, and in the community, thereby improving overall dietary patterns and subsequent risk of chronic disease and early mortality.             


OCTOBER 2019

Reviewer: Paul McCarthy, MD; Assistant Professor of Medicine; West Virginia University Heart and Vascular Institute, Morgantown, WV

Reference: Ohbe H, Jo T, Matsui H, Yasunaga H. Early Enteral Nutrition in Patients Undergoing Sustained Neuromuscular Blockade: A Propensity-Matched Analysis Using a Nationwide Inpatient Database. Crit Care Med. 2019 Aug;47(8):1072-1080. doi: 10.1097/CCM.0000000000003812

Why is this paper important? Due to the severity of illness of patients managed with sustained neuromuscular blocking agents (NMBAs) and the assumption of many clinicians that NMBA are associated with gastric dysfunction, it is common practice for many to delay enteral nutrition in patients receiving sustained NMBAs.  

There is limited data supporting early or delayed enteral nutrition (EN) in this patient population. This large propensity-matched analysis showed that early EN was associated with a lower mortality than delayed EN is this patient population.

Summary: Since no consensus on the optimal timing of enteral nutrition in patients managed with sustained NMBAs exists, the authors evaluated the association between EN started within 2 days of sustained NMBAs treatment and after 2 days of NMBA and in-hospital mortality.  The study was a retrospective review of an administrative database including over 1,200 acute care hospitals in Japan. The review included more than 2,300 patients from July 2010 to March 2016. In the database, there were 2,340 patients that receive sustained NMBA and a total of 378 patients (16%) had received early EN. A match of 374 early EN and 1122 delayed EN patients were paired for a one-to-three propensity score.  

There was no significant difference in the rate of hospital pneumonia between the two groups (risk difference, 2.8%; 95% CI, –2.7% to 8.3%).  There was also no significant difference in the intensive care unit (ICU) length of stay or duration of mechanical ventilation in survivors.  There was a significantly lower mortality rate in the early EN group compared to the delayed EN group (risk difference, –6.3%; 95% CI, –11.7% to –0.9%). There was also a significantly shorter hospital length of stay for survivors in the early EN group compared to the delayed EN group (risk difference, –11.4 d; 95% CI, –19.1 to –3.7 d). From the analysis of this retrospective database the authors conclude that early EN may be associated with a lower in-hospital mortality.

Commentary: The sustained use of NMBAs is generally discouraged in the ICU due to complications such as ICU-acquired weakness and prolonged mechanical ventilation associated with the therapy. The therapy is, however, used for indications such as intracranial pressure management, reducing metabolic demands, shivering control in targeted temperature management and ventilator dysynchrony in early acute respiratory distress syndrome.  

While studies in many ICU populations generally favor early EN this is the first study to my knowledge that specifically looks at patients undergoing sustained NMBAs.  Many clinicians do not prescribe EN for patients on sustained NMBAs due to concern for decreased gastric and intestinal peristalsis. The movement of skeletal muscle is controlled by acetylcholine stimulating nicotinic receptors and smooth muscle in the gastrointestinal tract is controlled by acetylcholine stimulating muscarinic receptors. Nondepolarizing NMBAs are competitive antagonists of nicotinic receptors which are stimulated by acetylcholine which control skeletal muscle. They do not complete with muscarinic receptors and do not relax smooth muscle.  Other factors that often accompany the use of NMBA use such as immobility, opioid use and positive fluid balance are associated with decreased gastric function, reflux and complications such as vomiting and pneumonia. This has not specifically been shown to occur because of NMBAs. This study showed no association with early EN and pneumonia. This review shows that early EN is likely safe and possibly could decrease mortality compared with a strategy of delayed EN. These results have been seen with early EN in other ICU populations.  

This study was a retrospective observational study and does have limitations. The patients were primarily medical and patients with traumatic brain injury, burns, severe trauma and recent intraabdominal surgery were excluded. Total caloric and protein intake were not considered and baseline nutritional status was not addressed. There was no standard protocol for the delivery of EN and delayed EN may have occurred in patients due to reasons related to their specific illness while others may be related to physician practice. There was no consideration for the dose of NMBA or if NMBA were given as continuous infusion or bolus. The study does, however, support the consideration of early EN when NMBAs are used and continued study of the topic.             


SEPTEMBER 2019

Reviewer: Berkeley N. Limketkai, MD, PhD; Associate Clinical Professor of Medicine, Division of Digestive Diseases; University of California Los Angeles, Los Angeles, CA. 

Reference: Levine A, Wine E, Assa A, et al. Crohn’s Disease Exclusion Diet Plus Partial Enteral Nutrition Induces Sustained Remission in a Randomized Controlled Trial. Gastroenterology. Aug 2019. doi: 10.1053/j.gastro.2019.04.021

Why is this paper important? Exclusion enteral nutrition (EEN) is effective for induction of remission in Crohn’s disease, but it is challenging for patients to consume long-term due to poor tolerability. This randomized trial demonstrated the benefit of partial enteral nutrition (PEN) with the Crohn’s disease exclusion diet (CDED) as an alternate therapeutic option. 

Summary: In this randomized controlled trial, 78 pediatric patients with mild-to-moderate Crohn’s disease were randomly assigned to either receive PEN (n=40) or EEN (n=38) for 12 weeks. Patients in the PEN group received 50% enteral nutrition and 50% CDED for 6 weeks, followed by 25% enteral nutrition and 75% CDED for the subsequent 6 weeks. Patients in the EEN group received 100% enteral nutrition for 6 weeks followed by 25% enteral nutrition and unrestricted solid foods during weeks 6 and 12. Four patients in the EEN group withdrew within 48 hours of the trial due to inability to continue EEN. In the intention-to-treat analyses, PEN was significantly better tolerated than EEN after 6 weeks (97.5% vs. 73.7%; P=0.002). When comparing PEN with EEN, there was no difference in clinical response (85.0% vs. 85.3%; P=0.97) and corticosteroid-free remission (80.0% vs. 73.5%; P=0.51). By week 12, following the reduction of enteral nutrition in both treatment arms, patients receiving PEN with CDED had greater sustained remission than those receiving enteral nutrition and an unrestricted diet (75.6% vs. 45.1%; P=0.01). Median C-reactive protein and fecal calprotectin concentrations declined from baseline in both treatment groups. The microbiome profiles changed similarly in both groups at week 6, although Proteobacteria remained reduced in the PEN group and Proteobacteria rebounded toward baseline levels in the EEN group by week 12.

Commentary: EEN has previously been demonstrated to be effective for inducing remission in children with Crohn’s disease and European guidelines already recommend it as a first-line treatment. However, EEN – with its absolute restriction of solid foods – can be challenging to sustain over time. A premise of PEN is the combination of EEN’s putative benefits on inflammation with the improved tolerability of solid foods. Given that the hypothesized mechanism of action for EEN is the reduced consumption and intestinal exposure to more pro-inflammatory food antigens, PEN therapy would need to be coupled with a solid food diet with a low pro-inflammatory burden, such as the CDED. Fortunately, the trial demonstrated PEN with CDED to be effective for both induction and maintenance of remission in children with Crohn’s disease over a 12-week period. EEN was similarly effective for inducing remission by week 6, but when enteral nutrition was thereafter combined with an unrestricted solid food diet, it was found to be inferior for sustaining remission. These findings are consistent with the hypothesis that the reduction of food antigens in EEN, PEN, and CDED may facilitate mucosal healing in Crohn’s disease. The study thus presents PEN with CDED as a compelling alternative to EEN that is more tolerable yet similar in efficacy. PEN with CDED may also be more practical for longer-term consumption and maintenance of remission. This study additionally provides insight into an environmental factor that may contribute to the pathogenesis of Crohn’s disease: the diet. While the findings are compelling, there are several limitations to consider, such as the lack of endoscopic data to confirm mucosal healing, small sample size, and study population limited to children. Replication studies are needed to continue building evidence toward (or against) PEN and CDED becoming recommended practices. Moreover, as EEN has lower efficacy in adults than children, further research is needed in adults before similar conclusions of efficacy can be extrapolated to this population. The position of dietary therapy in the overall treatment algorithm for Crohn’s disease and the patient or disease characteristics that would benefit from such therapies are still unclear and unanswered. What the growing evidence nonetheless confirms is the fact that the diet matters.


AUGUST 2019

Reviewer: Manpreet S. Mundi, MD; Associate Professor of Medicine, Division of Endocrinology, Diabetes, Metabolism, and Nutrition; Mayo Clinic, Rochester, MN.

Reference: Koutoukidis DA, Astbury NM, Tudor KE, et al. Association of Weight Loss Interventions With Changes in Biomarkers of Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis. JAMA Intern Med. July 2019. doi:10.1001/jamainternmed.2019.2248

Why is this paper important? This meta-analysis reveals the beneficial impact of weight loss through any intervention on non-alcoholic fatty liver disease (NAFLD). 

Summary: The currently reviewed manuscript is a meta-analysis that included randomized control trials (RCTs) focused on treatment of adult patients with NAFLD through weight loss.  They included trials focused on lifestyle modification through behavioral weight loss programs (BWLP), pharmacotherapy, bariatric surgery, or the combinations of these modalities.  The following outcome variables were assessed; alanine aminotransferase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), γ-glutamyl transferase (GGT), the Enhanced Liver Fibrosis score, the NAFLD fibrosis score, the Fatty Liver Index, liver stiffness, radiologically or histologically measured steatosis, inflammation, ballooning, fibrosis, and the NAFLD Activity Score (NAS). Additional outcomes evaluated included body weight and insulin-resistance markers (hemoglobin A1c, fasting glucose, fasting insulin, and the homeostatic model assessment for assessing insulin resistance [HOMA-IR] or equivalent). 

After screening 2096 titles, 22 studies (20 full text articles and 2 abstracts) were including consisting of 2588 participants.  15 studies tested BWLP, 6 tested pharmacotherapies (including liraglutide – 2 studies, Orlistat – 3 studies, and Sibutramine – 1 study), and one study tested intragastric balloon.  The median (IQR) intervention duration was 6 (3-8) months and resulted in in significant weight loss (-3.61 kg; 95% CI, -5.11 to -2.12).   Weight loss interventions were statistically significantly associated with improvements in biomarkers, including alanine aminotransferase (–9.81 U/L; 95% CI, –13.12 to –6.50), histologically or radiologically measured liver steatosis (standardized mean difference: –1.48; 95% CI, –2.27 to –0.70), histologic NAFLD activity score (–0.92; 95% CI, –1.75 to –0.09), and presence of nonalcoholic steatohepatitis (OR, 0.14; 95% CI, 0.04-0.49). No statistically significant change in histologic liver fibrosis was found (–0.13; 95% CI, –0.54 to 0.27).

Commentary: As the obesity epidemic continues to increase in prevalence worldwide, the health care community is underprepared for its full impact given association with a number of co-morbidities ranging from diabetes to endometrial cancer. One of these comorbidities is a spectrum of diseases categorized as non-alcoholic fatty liver disease (NAFLD) which ranges from fatty liver (steatosis) to inflammation and fibrosis (steatohepatitis; NASH) and can also progress to liver cirrhosis.  NAFLD is a manifestation of metabolic syndrome with insulin resistance playing a key pathogenic role.  As individuals gain weight and develop insulin resistance through consumption of excess calories and decrease caloric expenditure, there is increased free fatty acid (FFA) delivery to the liver.  Key isotope labeled trials have shown that these FFA arrive from three distinct sources including release from adipose tissue, dietary fat, and de novo lipogenesis from excess carbohydrates.  As FFA arrive, they are taken up by the liver in proportion to their rate of deliver and stimulate hepatocyte very low density lipoprotein (VLDL) triglyceride synthesis.  Unfortunately, as the delivery of these energy substrates exceeds the liver’s capacity to handle them, the storage pool continues to grow, and their metabolites begin to cause liver injury.  In addition to simply excess calories, certain combinations often found in fast food (red meat, trans-fat, high fructose corn syrup, highly refined carbohydrates, low fiber, and high energy density) may be the most deleterious when combined with sedentary behavior.  

It is due to this direct correlation of NAFLD with weight gain and insulin resistance, that weight loss is the treatment of choice.  Key studies like the one reviewed here are highlighting the benefits of even modest weight loss (5-10%) in reversing NAFLD.  However, it is important to highlight that this level of weight loss cannot be achieved through simple advice from a clinician during one visit.  Instead, intensive behavior therapy that typically consists of weekly visits for 3-6 months and focuses on improvement in diet (especially avoiding “fast-food”) and increase in activity level is needed to achieve 5-10% in most patients.  Even despite the use of these intensive BWLP such as those offered by the LOOK Ahead trial and the Diabetes Prevention Program (DPP), not all patients will respond.  Therefore, it is key for the clinical to follow their patients closely and if they are not losing weight to escalate the intensity by adding weight loss medications and/or proceed to endoscopic or surgical intervention.  Additionally, even patients who respond initially may have weight regain over the long run.  These patients often feel quite discouraged and may not seek additional care. It is important to follow these patients long-term as with weight regain, there is often return of weight related co-morbidities.  


JULY 2019

EATing in the ICU: TARGETs for Measuring Energy, Nutrition Dose, and Clinical Outcomes

Reviewer: Jayshil (Jay) Patel, MD
Associate Professor of Medicine, Division of Pulmonary & Critical Care Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin

Reference: Allingstrup MJ, Kondrup J, Wiis J et al. Early goal-directed nutrition versus standard of care in adult intensive care unit patients: the single-center, randomized, outcome assessor-blinded EAT-ICU trial. Intensive Care Med. 2017;43:1637-1647

Why is this paper important?  The 2016 ASPEN and 2019 ESPEN critical care nutrition support guidelines agree that indirect calorimetry (IC) be used to assess energy requirements but disagree in nutrition dose during the first week of critical illness.  The EAT-ICU trial was the first randomized controlled trial that compared IC-derived early-goal directed nutrition (EGDN) to meet full energy requirement versus standard of care nutrition delivery in mechanically ventilated critically ill adults with an expected length of ICU stay of 3 or more days. 

Summary: Citing observational studies showing benefits of achieving IC-derived energy and protein goals in critically ill adults, the EAT-ICU study sought to answer the question: In mechanically ventilated critically ill adults expected to remain in the ICU for at least 3 days, does intervention with EGDN, compared to standard of care, improve the primary outcome of physical quality of life score6-months after randomization?  There were numerous secondary outcomes, including 28-day, 90-day and 6-month mortality and length of ICU stay.  Under concealed allocation, patients were randomized 1:1 to EGDN or standard nutrition therapy. 

The EGDN arm aimed to deliver 100% of IC-derived energy requirements within 24-hours using enteral and supplemental parenteral nutrition.  EGDN patients underwent daily 24-hour urea excretion and were prescribed protein at 1.5 g/kg/day regardless of urea excretion.  The standard nutrition therapy arm had energy requirements calculated using 25 kcal/kg/day and had EN started within 24-hours and received supplemental PN if the calculated energy requirement goal was not met by day 7.  Both arms had the same blood glucose targets, received trace elements as needed, had gastric residual volumes measured, and received prokinetic agents at the clinicians’ discretion. 

Over approximately three years, 586 patients were eligible and 203 were randomized: 102 to EGDN and 101 to standard of care.  The mixed medical-surgical ICU patients had comparable baseline characteristics: EGDN and standard nutrition therapy groups were 63 and 68 years old, respectively; and both groups had a median BMI of 22 kg/m2. Of all patients, 47% had severe sepsis and had a SOFA score of 8.  Over the first 7-days of ICU admission, IC-derived energy requirement was 2069 kcal in the EGDN group, compared to 1887 kcal in standard of care.  Calculated EGDN group energy requirement was 1950 kcal, compared to 1875 kcal in standard of care.  Energy balance was -66 kcal/day in EGDN, compared to -787 kcal/day in standard of care.  Protein intake was 1.47 g/kg/day in EGDN, compared to 0.50 g/kg/day in standard of care.  There was no difference in the primary outcome of 6-month physical quality life score between EGDN and standard of care (22.9 vs 23, p=0.99).  There were no differences in 28-day, 90-day, or 6-month mortality rate between groups. EGDN had better cumulative energy and protein balance compared to standard of care.  More EGDN patients had at least one episode of hyperglycemia compared to standard of care (52 vs 25%, p=0.0001) and received higher doses of insulin (86 vs 0 international units, p=0.008). 

The authors concluded EGDN, compared to standard of care, led to more energy and protein delivery and lower nutritional deficits in mechanically ventilated ICU adults but no differences in the primary outcome of physical quality of life at 6 months or secondary outcomes of mortality, organ failure, complications or length of ICU stay. 

Commentary: The EAT-ICU trial results shed light on four important critical care nutrition questions: [1] Is IC needed to estimate energy requirements in critically ill patients? [2] What is the optimal nutrition dose during the first week of critical illness? [3] What is the role for supplemental parenteral nutrition during the first week of critical illness? and [4] What outcome measures should critical care nutrition trials evaluate? 

First, the 2016 ASPEN and 2019 ESPEN critical care nutrition support guidelines recommend using IC to define energy requirement.  Despite these recommendations, lack of resources and personnel and the cumbersome nature of conducting IC may limit widespread use, prompting bedside clinicians to utilize predictive equations to estimate energy requirements.  EAT-ICU results challenge guidelines’ call for IC use to estimate energy requirements in critically ill patients by finding a difference of 119 kcal between IC-derived and calculated (25 kcal/kg/day) energy requirement in the EGDN group (2069 vs 1950 kcal), suggesting there’s no clinical difference in deriving energy estimation between the two methods.  However, EAT-ICU was a single-center study where medical-surgical patients had a mean BMI of 22 kg/m2 and a SOFA score of 8.  Therefore, it is important to consider the patient population before concluding IC and equation-derived energy requirements are equal.  In fact, sicker patients with greater catabolic burden or those with lower or higher BMI may have drastically different IC- and equation-derived energy requirements.  The EAT-ICU investigators should be congratulated for developing transparent and reproducible protocols to identify energy requirements, which paves the path for future EGDN studies.   

Next, ASPEN and ESPEN guidelines provide disparate recommendations for nutrition dose in critically ill adults.  When IC is used, the ESPEN guideline recommends isocaloric nutrition be progressively implemented after the early phase of acute illness, but when a predictive equation is used to estimate energy requirements, hypocaloric nutrition is preferred (over isocaloric) during the first week of ICU admission.  The ASPEN guideline does not distinguish between IC- or predictive equation-based energy requirements and nutrition dose.  Rather, the 2016 ASPEN guideline calls for determining nutritional risk using NUTRIC or NRS-2002 scores and recommends optimizing nutrition dose (>80% estimated or calculated energy goal) within 48-72 hours in patients deemed high-nutritional risk.  EAT-ICU did not find any difference in primary or secondary outcomes despite EGDN patients receiving 90% of both energy and protein prescriptions, compared to standard of care receiving 56 and 43% of energy and protein prescriptions, respectively.  A “one size fits all” nutrition dose may not be appropriate since no two ICU patients are alike.  EAT-ICU randomized medical-surgical ICU patients to EGDN or standard of care and a signal for benefit may have been lost in patient heterogeneity.  Rather, sicker patients at nutritional risk may derive greater benefit from energy and protein optimization.  Observational studies using NUTRIC to stratify patients to high and low nutritional found an association between more energy and protein and reduced mortality.  Studies comparing EGDN to standard of care in patients most likely to benefit from nutrition optimization (i.e., high nutritional risk) are warranted.

Third, both ASPEN and ESPEN critical care guidelines recommend commencing enteral nutrition within 24-48 hours in critically ill adults unable to maintain volitional intake.  ASPEN recommends waiting 7-10 days and ESPEN recommends starting supplemental PN on a case-by-case basis.  As with other supplemental PN trials (EPaNIC, SPN, TOP-UP), EAT-ICU weaves an important thread into the fabric of critical care nutrition trials that have demonstrated feasibility of using supplemental PN to meet energy requirements during the first week of critical illness.  The EGDN nutrition protocol were started 16 hours after ICU admission (table S2) and 95% of EGDN patients adhered to the protocol to achieve >90% IC-measured energy requirement during the first week of critical illness.  However, findings from the EAT-ICU trial challenge guideline recommendations for supplemental PN use during the first week of critical illness.  EAT-ICU showed no differences in primary or secondary outcomes between EGDN and standard of care arms despite greater nutrition delivery using supplemental PN in the EGDN group during the first week of critical illness.  Even though there were no significant differences in nosocomial infections between groups, there were more hyperglycemia episodes and greater insulin use in the EGDN group, which are likely due to PN use.  The contrast in blood glucose level was not associated with differences in clinical outcomes but does suggest pushing nutrition dose closer to full energy requirement during the first week of critical illness may worsen intolerance.

Finally, the EAT-ICU investigators evaluated the effect of greater nutrition during the first week of critical illness on physical functioning at 6-months.  With enhanced vigilance and better support systems, ICU mortality has decreased over time.  In EAT-ICU, the observed 28-day mortality was approximately 20%.  In general, a lower baseline event rate makes it challenging to design critical care nutrition trials that are powered for mortality benefit.  Stated differently, to test the hypothesis that nutrition therapy reduces mortality a few percentage points (from a baseline 20% mortality) would require thousands of patients.  EAT-ICU assessed a patient-centered outcome like physical function, which holds biologic plausibility as a primary outcome for a nutrition intervention.  Greater protein and energy delivery during critical illness could, in theory, maintain, if not enhance, lean muscle function; which may augment physical function.  However, the lack of benefit observed in EAT-ICU may lie in the timing of the primary outcome.  In other words, does a difference of 498 kcal at ICU day 7 translate into a difference in physical function at 6-months?  Future studies should evaluate the impact of nutrition dose on short and long-term non-mortality outcomes, including muscle content and bioenergetics and physical function.


JUNE 2019

Reviewer: Stephen A. McClave, MD; University of Louisville, Louisville, KY   

Reference: Chapman M, Peake S, and the Australian and New Zealand Intensive Care Society (ANZICS) Clinical Trials Group. Energy-Dense versus Routine Enteral Nutrition in the Critically Ill. The TARGET Trial. NEJM 2018;379:1823-34.

Why this paper is important: While study results indicate that an energy-dense formula is a successful strategy for meeting caloric requirements in critical illness, no outcome benefits were realized. The study suggests that feeding less calories is safe and better tolerated than full feeds and leads to a strategy that may pose less risk to the patient in the early phases of critical illness.

Summary: After completing a pilot trial which showed that a calorically-dense formula delivered calories closer to goal than a routine formula resulting in reduced mortality, the ANZICS group set up this TARGET Trial, a 4000 patient DBPRCT in 46 ICUs in Australia and New Zealand involving critically ill patients receiving invasive mechanical ventilation on EN, randomized to Augmented EN 1.5 kcal/ml (Fresubin® Energy Fibre) vs Standard EN  1.0 kcal/ml (Fresubin® 1000 Complete) with content of protein similar at 56 g/L vs 55 g/L, respectively. Patients on average were 75% medical, 67 years of age, had a BMI 29 with APACHE II score 22, and 62% were on vasopressor support. EN was started within 15 hours of admission to ICU and given for average of 6 days.  Study patients got 29.1 kcal/kg IBW/d while controls got 19.6, a difference of 46.7% more calories, both groups getting the same protein at 1.1 gm/kg IBW/d. The primary endpoint, 90-day all-cause mortality, was no different at 26.8% for study patients vs 25.7% for controls (with no differences found on 7 different subgroup analyses for age, disease severity, BMI, admission diagnosis, etc.).  No other outcomes were different between groups. Study patients on the energy-dense formula showed evidence of greater intolerance with increased gastric residual volumes, regurgitation, need for promotility agents, elevated glucose levels, and higher dose of insulin required than controls. Researchers concluded that use of the energy-dense formula was a successful strategy for delivering EN closer to goal than routine formulas, but the practice provided no mortality benefit.

Commentary: In their power analysis prior to the study which indicated that an enrollment of 3774 patients was needed, the authors accurately estimated the event rate for their primary endpoint of 90-day mortality between 20-30 % (actual study results 25.7%) but overestimated the treatment effect as being a reduction of 17% (actual was only 1.1%). This means that despite the 3957 patients that ultimately were entered, the study was still underpowered to show a difference between groups. As patients in the control group received 47% less calories than study patients, the study represents yet another trial where the permissive underfeeding of calories yields the same outcome as patients receiving full feeds. Such findings suggest that the amount of feeding is less important than timing, which may be explained by the possibility that underfeeding still provides the non-nutritional benefits of enteral feeding at a low dose (to maintain gut defenses and microbiome) and that the nutritional benefits at full dose (to maintain lean body mass and maximize protein synthesis) are less important in the early phases of critical illness. Slower ramp-ups and less feeding may be a more optimal strategy to avoid overfeeding, risk of ischemia or refeeding syndrome, to support autophagy, and to monitor tolerance as feedings are advanced. Reaching the protein goal may be more important early in the ICU than reaching caloric goal, and keeping the caloric goal at less than 70-80% of energy requirements may have better outcome than delivering full caloric regimen.  Mitochondrial failure in the early phases of critical illness may mean that patients are not ready to assimilate full nutritional therapy. An emphasis on getting EN started shortly after admission to the ICU should quickly shift to adding supplemental therapy to maintain the gut barrier, prevent disordered immune responses, and promote commensalism (such as soluble prebiotic fiber, probiotics, pegylated phosphate, intact food formulas, and even fecal microbial transplantation). 


MAY 2019

Reviewers: D. Clark Files, MD; Wake Forest School of Medicine, Winston-Salem NC 27157
Sadeq Quraishi, MD, MHA, MMSc; Harvard Medical School, Boston MA 02114

Authors: Arabi YM, Al-Balwi M, Hajeer AH, Jawdat D, Sadat M, Al-Dorzi HM, Tamim H, Afesh L, Almashaqbeh W, Alkadi H, Alwadaani D, UdayaRaja GK, Abdulkareem IBA, Al-Dawood A.

Title: Differential Gene Expression in Peripheral White Blood Cells with Permissive Underfeeding and Standard Feeding in Critically Ill Patients: A Descriptive Sub-study of the PermiT Randomized Controlled Trial. Sci Rep. 2018;8(1):17984.

Why is the paper important: This secondary mechanistic analysis of gene expression from patients enrolled in the PermiT trial suggests broad biological differences that occur in response to feeding strategies, supporting the central importance of enteric nutrition on regulation of critical biological pathways.

 

Summary and Commentary:

In this study1, Arabi et al., performed a secondary analysis of peripheral blood mononuclear cell (PBMC) gene expression from participants included in the PermiT trial.2 PermiT was a 7 center, international, randomized, controlled trial of mechanically ventilated patients (n=894) comparing a permissive underfeeding strategy (40-60% of caloric targets) to standard feeding strategy (70-100% of caloric targets). The PermiT investigators reported that 90-day mortality, as well as a number of secondary outcomes, did not differ between the treatment arms.

For the current manuscript, Arabi et al., analyzed over 1,700 peripheral blood mononuclear cell (PBMC) gene transcripts from 25 permissively underfed and 25 standard feeding participants in the PermiT trial. The most notable downregulated genes in the “underfed” group included those involved in phospholipase pathways (membrane associated phospholipase A1), autophagy inhibition (GADD45B), glycolysis (muscle pyruvate kinase), and inflammation (sPLA2-IIE), as compared to the standard feeding group. On the other hand, the most notable upregulated genes with “underfeeding” included Pan2, Cytochrome C, and VEGF-C, suggesting increased protein catabolism, mitochondrial activity, and endothelial cell proliferation, respectively, as compared to the standard feeding group.

Although the study suggests a potentially beneficial metabolic profile and autophagy promotion in the “underfed” group, several limitations are worth noting. First, the study cohort was limited to only 50 patients. Second, there was only a small difference between groups in terms of actual calories delivered, i.e. 57: IQR 51-59 % of calculated requirements in the “underfed” group vs. 68: IQR 57-90 % in the standard feeding group (p <0.001). Third, while protein delivery was not statistically significant between groups (82: IQR 69-89 % vs. 66: IQR 50-84 %; p=0.07, respectively), the “underfed” group received significantly higher amounts of protein as additional enteral supplements (31: IQR 22-40 g/day vs. 0: IQR 0-6 g/day; p<0.0001, respectively). And fourth, though not statistically significant, the “underfed” group had a numerically lower median age compared to the standard feeding group (28: IQR 23-58 years vs. 45: IQR 38-65 years; p=0.21, respectively). This may be important since impaired autophagy is implicated as an underlying driver of aging in multiple studies.3

Taken all together, these findings suggest that how protein is delivered, and potentially age, in addition to differences in caloric delivery may have played a role in the observed results. Of note, the authors suggest that a downregulation of GADD45B in the “underfed” group may signal enhanced autophagy. While GADD45B is an important regulator at the later parts of the autophagy pathway,4autophagy is a complex pathway involving many proteins. Therefore, it may be premature to conclude that this study demonstrates that “underfeeding” promotes autophagy through inhibition of this single gene. Nonetheless, these data support the concept that nutritional interventions delivered to critically ill patients likely have meaningful and broad impacts on important biological pathways. As such, more studies of this type are needed to better understand the biology of nutrition during acute illness.

 

1Arabi YM, Al-Balwi M, Hajeer AH, Jawdat D, Sadat M, Al-Dorzi HM, Tamim H, Afesh L, Almashaqbeh W, Alkadi H, Alwadaani D, UdayaRaja GK, Abdulkareem IBA, Al-Dawood A. Differential Gene Expression in Peripheral White Blood Cells with Permissive Underfeeding and Standard Feeding in Critically Ill Patients: A Descriptive Sub-study of the PermiT Randomized Controlled Trial. Sci Rep. 2018;8(1):17984.


2
Arabi YM, Aldawood AS, Haddad SH, Al-Dorzi HM, Tamim HM, Jones G, Mehta S, McIntyre L, Solaiman O, Sakkijha MH, Sadat M, Afesh L. Permissive Underfeeding or Standard Enteral Feeding in Critically Ill Adults. New England Journal of Medicine. 2015.


3
Levine B, Kroemer G. Biological Functions of Autophagy Genes: A Disease Perspective. Cell. 2019;176(1-2):11-42.


4
Keil E, Hocker R, Schuster M, Essmann F, Ueffing N, Hoffman B, Liebermann DA, Pfeffer K, Schulze-Osthoff K, Schmitz I. Phosphorylation of Atg5 by the Gadd45beta-MEKK4-p38 pathway inhibits autophagy. Cell Death Differ. 2013;20(2):321-32.

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