A total of 23 RCTs were included in the meta-analysis.
The mean percentage of patients with global improvement (21 trials) was 38% in the placebo group and 56% in the smooth muscle relaxant group. The pooled Peto odds ratio (OR) was 2.13 (95% confidence interval, CI: 1.77, 2.58, P=0.001) and the mean risk difference was 22% (95% CI: 13, 32, P<0.001).
The percentage of patients with pain improvement (11 trials) was 41% in the placebo group and 53% in the smooth muscle relaxant group. The Peto OR was 1.65 (95% CI: 1.30, 2.10, P<0.001) and the risk difference was 18% (95% CI: 7, 28, P<0.001).
The mean percentage of patients with improvement for abdominal distension was 35% in the placebo group, compared with 44% in the smooth muscle relaxant group. The Peto OR was 1.46 (95% CI: 1.10, 1.94, P=0.008).
There were no significant differences for improvements in constipation or transit, or for adverse events.