Cumulative meta-analysis. A statistically significant
effect of chewing gum on abdominal surgery was first observed
after publication of the first trial in 2002 (1.1 days reduction in
time to flatus, P < 0.01; 2.7 days reduction in time to bowel movement,
P < 0.01). Although subsequent trials had increased the precision
of the point estimate, no substantive change had occurred in
the direction or magnitude of the treatment effect. A statistically
significant effect on time to first flatus of chewing gum following
abdominal surgery was consistently observed after publication
of the seventh trial in 2006, third trial in 2006 on time to bowel
movement, and seventh trial in 2006 on LOS. (Fig. 7)