Systematic review: the methodological quality of trials affects estimates of treatment efficacy in functional (non-ulcer) dyspepsia

Aim: To evaluate treatment efficacy using objective quality criteria. Methods: A systematic review was performed of rand-omized controlled trials of endoscopically investigated dyspepsia (1979–2003) using the Jadad score and Rome II guidelines. The Jadad score differentiated studies as ‘high quality ’ (score 4–5/5) vs. ‘poor quality ’ (score 1–3/ 5). Three key Rome II guidelines on study design (cut-off of 0/3 or> 0/3) were also compared with the Jadad score. Results: Poor quality trials suggested a benefit of prokinetic therapy [relative risk (RR) of remaining dyspeptic, 0.47; 95 % confidence interval (CI), 0.39– 0.56), which was not confirmed in high quality trials (RR, 1.0; 95 % CI, 0.84–1.19). There was a marked benefit of H2-receptor antagonist therapy in poor quality trials (RR, 0.68; 95 % CI, 0.61–0.76), but a marginal benefit in good quality trials (RR, 0.87; 95 % CI, 0.79– 0.97). Trial quality did not affect the small statistically significant benefit seen with Helicobacter pylori eradica-tion. Two high quality trials suggested a limited benefit with the use of proton pump inhibitors, with no poor quality trials to provide a comparison. Separation of the studies by the Rome II criteria had a similar impact on the calculated treatment estimates. Conclusions: The magnitude of benefit of prokinetic and H2-receptor antagonist therapies reported in previous meta-analyses has been over-estimated. The quality of trials has an impact on the efficacy estimates of treatment. The Rome II criteria for study methodology may be appropriate for judging study quality