Herbal medicine for functional dyspepsia: Network meta-analysis of placebo-controlled randomised trials

Conventional treatments for functional dyspepsia (FD) are limited. Herbal medicine (HM) use is prevalent despite unclear comparative effectiveness among different formulae.

This network meta-analysis (NMA) aimed to evaluate the comparative effectiveness of HM formulae for FD against placebo.

Seven international and Chinese databases were searched for randomised controlled trials (RCTs) on HM versus placebo. Risk of bias among RCTs was assessed using Cochrane Risk-of-Bias Tool 2. Data from RCTs were extracted for random-effect pairwise meta-analyses. NMAs were performed to evaluate the comparative effectiveness of HM formulae. GRADE partially contextualised framework was adopted to facilitate NMA result interpretation.

Twelve different HM formulae were identified from fifteen RCTs of mediocre quality. At 8-week follow-up, pairwise meta-analyses indicated that HM was superior to placebo in alleviating global symptoms (pooled risk difference (RD): 0.20; 95% confidence interval (CI): 0.11-0.29), with effect size larger than the minimally clinically important difference of 0.20 RD. Sensitivity analysis showed no significant impact on results attributable to risk of bias. NMAs demonstrated that Xiao Yao Pill and Modified Ban Xia Xie Xin Decoction probably have a large beneficial effect on alleviating global symptoms (RD: 0.37; 95% CI: 0.03-0.99) and postprandial fullness (standardised mean difference: -0.93; 95% credible interval: -1.61 to -0.06), respectively. No serious adverse events were reported.

Xiao Yao Pill and Modified Ban Xia Xie Xin Decoction may be considered as an alternative among patients unresponsive to conventional treatments. The comparative effectiveness of these two formulae should be evaluated in future trials.