Therapeutic Benefits of Glutamine: An Umbrella Review of Meta‐Analyses

Abstract

IntroductionGlutamine may become a conditionally essential amino acid in patients with catabolic disease as it has been shown that circulating glutamine levels drop during critical illness and following major surgery and this may result in an increase in secondary infection risk, recovery time and mortality rates. However there is much discrepancy in the literature when it comes to randomized controlled studies and so this umbrella review of published meta‐analysis was performed to examine the effectiveness of glutamine's role as a therapeutic agent.MethodsA PubMed, Cochrane Library and CINAHL from January 1st, 1980 to September 30th, 2016 was conducted using the following search strategy: “glutamine AND (meta‐analysis OR systematic review)”. Only English language publications were retrieved which provided quantitative statistical analysis on pooled treatment effects on the relative risks and odds ratios of infectious complications, length of stay in hospital and mortality.ResultsTwenty‐one meta‐analyses were entered into this umbrella review. Fifteen of 19 meta‐analyses found statistically significant reductions of infectious complications with relative risks ranging between 0.42 and 0.93. Twelve of 18 meta‐analyses found statistically significant reductions in the length of stay in hospital with reductions ranging between 0.42 to 4.73 days. Only 4 of 15 meta‐analyses found statistically significant reductions in mortality with relative risks ranging between 0.64 and 1.01. Statistically significant heterogeneity was observed in 16 of 22 meta‐analyses, and publication bias was observed in 5 of 11 meta‐analyses.ConclusionGlutamine supplementation for critically ill or surgical patients through parenteral or enteral routes appears to reduce the rate of hospital acquired infectious complications and shortening of the length of stay in hospital. Glutamine supplementation also appeared to reduce the rate of in‐patient mortality, but the majority of meta‐analyses did not reach statistical significance. However, we must appreciate the positive results with some caution in light of the fact that there exists statistically significant heterogeneity for the majority of meta‐analyses, and statistically significant publication bias in almost half.Support or Funding InformationThere was no funding for this project.