A meta-analysis of the effect of combinations of immune modulating nutrients on outcome in patients undergoing major open gastrointestinal surgery.

Background: Immune modulating nutrition (IMN) has been shown to reduce complications after major surgery, but strong evidence to recommend its routine use is still lacking. Objective: The aim of this meta-analysis was to evaluate the impact of IMN combinations on postoperative infectious and noninfectious complications, length of hospital stay, and mortality in patients undergoing major open gastrointestinal surgery. Methods: Randomized controlled trials published between January 1980 and February 2011 comparing isocaloric and isonitrogenous enteral IMN combinations with standard diet in patients undergoing major open gastrointestinal surgery were included. The quality of evidence and strength of recommendation for each postoperative outcome were assessed using the GRADE approach and the outcome measures were analyzed with RevMan 5.1 software (Cochrane Collaboration, Copenhagen, Denmark). Results: Twenty-six randomized controlled trials enrolling 2496 patients (1252 IMN and 1244 control) were included. The meta-analysis suggests strong evidence in support of decrease in the incidence of postoperative infectious [risk ratio (RR) (95% confidence interval [CI]): 0.64 (0.55, 0.74)] and length of hospital stay [mean difference (95% CI): -1.88 (-2.91, -0.84 days)] in those receiving IMN. Even though significant benefit was observed for noninfectious complications [RR (95% CI): 0.82 (0.71, 0.95)], the quality of evidence was low. There was no statistically significant benefit on mortality [RR (95% CI): 0.83 (0.49, 1.41)]. Conclusions: IMN is beneficial in reducing postoperative infectious and noninfectious complications and shortening hospital stay in patients undergoing major open gastrointestinal surgery.