Glutamine supplements increase mortality in critically ill patients
medwireNews: Giving critically ill patients with multiorgan failure intravenous and enteral glutamine supplements increases mortality at 6 months, and antioxidant supplements have no effect, a study shows.
The finding is surprising because previous meta-analyses of randomized trials have indicated that glutamine and antioxidant supplements may improve survival in patients who are critically ill.
The study took place across 40 intensive care units (ICUs) in Canada, the USA, and Europe, and incorporated 1223 critically ill adults. Patients were randomly divided into four groups and given placebo, glutamine only (0.35 g per kg body weight per day), antioxidants only, or glutamine plus antioxidants. All groups received the supplements within 24 hours after ICU admission, and through both enteral and intravenous routes.
Patients assigned to receive antioxidants were given 500 µg selenium intravenously, and 300 µg selenium, 20 mg zinc, 10 mg β-carotene, 500 mg vitamin E, and 1500 mg vitamin C enterally.
Writing in TheNew England Journal of Medicine, Daren Heyland (Kingston General Hospital, Ontario, Canada) and colleagues report that there was a trend toward increased mortality at 28 days among patients who received glutamine (32.4 vs 27.2%), which reached significance at 6 months.
The frequency of high urea levels (>50 mmol/L) was greater among patients who received glutamine than those who did not, at 13% compared with 4%. Glutamine did not, however, have any effect on the rate of organ failure or the outcome of infections.
Antioxidants had no effect on mortality at any stage.
In an accompanying editorial, Greet van den Berghe (KU Leuven, Belgium) suggests that the low glutamine levels that have been observed in patients during critical illness, leading to the idea that glutamine supplementation could be beneficial, may "reflect an adaptive and beneficial stress response rather than a conditional deficiency."
In fact, in a substudy involving 66 patients, Heyland et al found that baseline median glutamine and selenium levels were within normal limits.
But for van den Berghe: "Probably the most important contribution of the present trial is that it provides firm support for the need for large, adequately powered, randomized, controlled trials in critical care medicine to investigate whether what we intuitively consider to be the best treatment for our patients also is truly effective and without harm."
medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013
By Afsaneh Gray, medwireNews Reporter