Nine RCTs (n=773) were included.
The quality scores ranged from 1 to 3 out of a possible 5: six studies scored 3; two scored 2; and one study scored 1.
No statistically significant difference was observed in H. pylori eradication between pre-treatment and no pre-treatment (RD 0.1%, 95% CI: -5, 5). Statistically significant heterogeneity was found. Heterogeneity was largely due to two studies that reported the largest RDs (-18% and 33%, respectively); other studies reported RDs ranging from -8 to 10%.
There were no statistically significant differences for subgroup analyses of studies of patients with peptic ulcer disease or either peptic ulcer disease or functional dyspepsia, or for studies using different regimens ('quadruple therapy', 'modern triple therapies', PPI, clarithromycin plus amoxicillin, and PPI, a macrolide plus a nitroimidazole).
The authors reported that the funnel plot was 'fairly symmetrical' with smaller studies showing more variation.