Eighteen relevant studies were identified (n=2,746 patients), including 15 RCTs (n=2,628 patients, range 7 to 569) and three open-label trials (n=118, range 16 to 62) of central nervous system (CNS) drugs. There were four RCTs of CNS drugs (n=219 patients) and eleven RCTs of classic drugs (n=2,409 patients). The classic drugs RCTs included six of prokinetic drugs and five of antisecretory drugs. Twelve RCTs were reported as double-blind and one as blind. Eight RCTs were placebo-controlled, with three cross-over studies, one parallel study and one multicentre study.
CNS drugs significantly reduced dyspeptic symptoms/pain scores (SMD 1.48, 95% CI 0.75 to 2.22; four RCTs; random-effects model). No significant heterogeneity was found.
Prokinetic drugs (SMD 1.63, 95% CI 1.28 to 1.97; six RCTs) and antisecretory agents (SMD 0.93, 95% CI 0.57 to 1.29; five RCTs) significantly reduced dyspeptic symptoms/pain scores. Both analyses used a random-effects model and had significant heterogeneity.
Sensitivity analyses did not change the overall effects. There was no significant difference between prokinetic drugs and CNS drugs, but there was a significant difference between antisecretory drugs and CNS drugs (p<0.01); CNS drugs were slightly more effective (further details were not provided).
The pooled analysis of the RCTs and the open studies of CNS drugs gave a slightly higher effect in reducing dyspeptic symptoms (SMD 1.96, 95% CI 0.82 to 3.11; seven studies; random-effects model); there was significant heterogeneity.
There was no evidence of publication bias.