Effect of Perioperative Nutritional Supplementation on Postoperative Complications—Systematic Review and Meta-Analysis

Perioperative carbohydrate loading, increased protein intake, and immunonutrition may decrease postoperative complications. Studies on the topic have led to controversial results. We searched Medline, EMBASE, and CENTRAL up to August 2018 for randomized trials comparing the effect of perioperative nutritional supplements (intervention) versus control on postoperative complications in patients undergoing gastrointestinal cancer surgery. Secondary outcomes included infectious complications and length of hospital stay (LOS). Random effects model was used to estimate the pooled risk ratio (RR) of treatment effects. Pooled mean difference (MD) was used to compare LOS. Heterogeneity was assessed using I 2. Sources of heterogeneity were explored through subgroup analysis by nutritional supplementation protocol, type of surgery, and type of nutritional supplement. Risk of bias and quality of the evidence were assessed. Of 3951 articles, we identified 56 trials ( n  = 6370). Perioperative nutrition was associated with a lower risk of postoperative complications (RR 0.74, 95% confidence interval (CI) 0.69–0.80); postoperative infections (RR 0.71, 95% CI 0.64–0.79, n  = 4582); and postoperative non-infectious complications (RR 0.79, 95% CI 0.71–0.87, n  = 4883). There were no significant heterogeneity outcomes analyzed ( I 2  = 14%, 1%, and 7%, respectively). LOS was shorter for the intervention group, MD − 1.58 days; 95% CI − 1.83 to − 1.32; I 2  = 89%). Subgroup analysis did not identify sources of heterogeneity. The quality of evidence for postoperative complications was high and for LOS was moderate. Perioperative nutritional optimization decreases the risk of postoperative infectious and non-infectious complications. It also decreases LOS in patients undergoing gastrointestinal cancer surgery, but these findings should be taken with caution given the high heterogeneity.