A systematic literature review and meta-analysis of randomized clinical trials of parenteral glutamine supplementation.

Systematic review and meta-analysis of 40 randomized clinical trials in 3107 analyzable adults receiving parenteral nutrition in ICU or surgical settings. Populations included major surgery, critical illness, trauma, burns, pancreatitis, and mixed surgical/critical illness groups.

Parenteral glutamine was added to parenteral nutrition in randomized trials of critically ill and surgical adults. Doses ranged from 0.13 to 0.57 g/kg body weight per day, with many trials treating for more than 9 days; the comparator was parenteral nutrition without glutamine or usual control nutrition support.

Parenteral glutamine reduced infectious complications and shortened hospital length of stay, but it did not significantly reduce short-term mortality overall. Pooled results showed mortality RR 0.89 (95% CI 0.77 to 1.04; p = 0.145), infections RR 0.83 (95% CI 0.72 to 0.95; p = 0.009), and hospital LOS MD = −2.35 days (95% CI −3.68 to −1.02; p = 0.001). Benefits were more apparent in some subgroup analyses at doses >0.20 g/kg BW/day and durations >9 days. The authors concluded that parenteral glutamine may help reduce morbidity, but its overall effectiveness in intensive care remains uncertain.

Mortality was not significantly improved overall, and results were influenced by the SIGNET trial. The evidence base was heterogeneous across patient types, doses, and treatment durations, and potential publication bias could not be excluded. Adverse-event reporting was inconsistent, limiting safety synthesis.