Gum Chewing and Coffee Consumption but not Caffeine Intake Improve Bowel Function after Gastrointestinal Surgery: a Systematic Review and Network Meta-analysis

Background Postoperative ileus is common after gastrointestinal surgery. This network meta-analysis aimed to compare the effectiveness of gum chewing and coffee and caffeine intake on ileus-related outcomes. Methods A systematic literature review was performed to identify randomized controlled trials (RCTs) comparing noninvasive treatments for ileus after gastrointestinal surgery. The main analyses included random effects network meta-analyses using frequentist methods with simultaneous direct and indirect comparisons of time to first flatus, time to first defecation, and length of stay. Bayesian network meta-analysis using Markov chains was also used. Results A total of 32 RCTs comparing 4999 patients were included in this network meta-analysis. Time to flatus was reduced by gum chewing (mean difference compared to control (MD): -11 h, 95% confidence interval (95% CI) − 16 to − 5 h, P