Five RCTs were included in the review (n=158, sample size 19 to 43). One study had a Jadad score of 4, two scored 3 and two scored 2. Only one RCT used blinding of observers and included a placebo group. Only one study clearly accounted for dropouts.
Chewing gum versus controls (five RCTs)
Pooling of RCTs using a random-effects model found that the time to first passage of flatus and first bowel movement were both significantly shorter in the intervention group (WMD -0.66 days, 95% CI: -1.11 to -0.20, p=0.005 for flatus and WMD -1.10, 95% CI: -1.79 to -0.42, p=0.002 for bowel movement). However, both analyses had statistically significant heterogeneity (Χ2 test p<0.001). Findings for duration of hospital stay were not statistically significant.
The results of sensitivity analyses were also reported.
Results of a fixed-effect model were similar. Funnel plots showed no indication of publication bias.