The impact of perioperative glutamine-supplemented parenteral nutrition on outcomes of patients undergoing abdominal surgery: a meta-analysis of randomized clinical trials.

The objective of this study was to evaluate the impact of perioperative glutamine-supplemented parenteral nutrition (GLN-PN) on clinical outcomes in patients undergoing abdominal surgery. MEDLINE, EMBASE, and the Cochrane Controlled Clinical Trials Register were searched to retrieve the eligible studies. Eligible studies were randomized controlled trials (RCTs) that compared the effect of GLN-PN and standard PN on clinical outcomes in patients undergoing abdominal surgery. Clinical outcomes of interest were postoperative mortality, length of hospital stay, morbidity of infectious complication, and cumulative nitrogen balance. Statistical analysis was conducted by RevMan 5.0 software from the Cochrane Collaboration. Sixteen RCTs with 773 patients were included in this meta-analysis. The results showed a significant decrease in the infectious complication rates of patients undergoing abdominal surgery receiving GLN-PN (risk ratio [RR], 0.48; 95% confidence interval [CI], 0.32 to 0.72; P = 0.0004). The overall effect indicated glutamine significantly reduced the length of hospital stay in the form of alanyl-glutamine (weighted mean difference [WMD], -3.17; 95% CI, -5.51 to -0.82; P = 0.008) and in the form of glycyl-glutamine (WMD, -3.40; 95% CI, -5.82 to -0.97; P = 0.006). A positive effect in improving postoperative cumulative nitrogen balance was observed between groups (WMD, 7.40; 95% CI, 3.16 to 11.63; P = 0.0006), but no mortality (RR, 1.52; 95% CI, 0.21 to 11.9; P = 0.68). Perioperative GLN-PN is effective and safe to shorten the length of hospital stay, reduce the morbidity of postoperative infectious complications, and improve nitrogen balance in patients undergoing abdominal surgery.