BACKGROUND AND AIMS Treatment of functional dyspepsia with acid inhibitors is controversial and it is not known if the presence ofHelicobacter pylori infection influences the response.

RESULTS The proportions of patients considered to be in remission (intention to treat) at the end of treatment with placebo, ranitidine 150 mg, omeprazole 10 mg, and omeprazole 20 mg were, respectively, 42%, 50%, 48%, and 59% in the H pylori positive group and 66%, 73%, 64%, and 71% in the H pylori negative group. In H pyloripositive patients, the therapeutic gain over placebo was significant for omeprazole 20 mg (17.6%, 95% confidence intervals (CI) 4.2–31.0; p<0.014 using the Bonferroni-adjusted p level of 0.017) but not for omeprazole 10 mg (6.8%, 95% CI −6.7–20.4) or ranitidine 150 mg (8.9%, 95% CI −4.2–21.9). There was no significant therapeutic gain from active treatment over placebo in H pylori negative patients. Complete disappearance of symptoms and improvement in quality of life also occurred most frequently with omeprazole 20 mg and was significant in both H pylori positive and H pylori negative groups. The six month relapse rate of symptoms requiring treatment was low (<20%) in all groups.

CONCLUSIONS Omeprazole 20 mg per day had a small but significant favourable effect on outcome in H pylori positive patients. The differential response in these patients may be explained by an enhanced antisecretory response in the presence of H pylori. The effect of weaker acid inhibition was unsatisfactory.