Effect of profound acid suppression in functional dyspepsia: a double-blind, randomized, placebo-controlled trial

Functional dyspepsia (FD) is defined as persistent or recurrent pain/discomfort centred in the upper abdomen, where no structural explanation for the symptoms is found. The role of drug treatment remains controversial. The aim in this study was to evaluate the effect of omeprazole 20 mg twice daily (b.i.d) and to test methods for symptom assessment.

197 patients fulfilling the criteria for FD were randomly allocated to double-blind treatment with omeprazole 20 mg b.i.d (n = 100) or placebo (n = 97) for 14 days. Patients with a known gastrointestinal disorder or with main symptoms indicating gastro-oesophageal reflux disease or irritable bowel syndrome were excluded. Helicobacter pylori testing and 24-h intra-oesophageal 24-h pH-metry were performed before randomization. The patients recorded dyspeptic symptoms on diary cards.

A stringent endpoint, 'complete symptom relief on the last day of treatment', was the primary efficacy variable. For the APT cohort, this was achieved in 29.0% and 17.7% on omeprazole and placebo, respectively (95% CI of difference (11.3%): -0.4%-23.0%, P = 0.057). Similar figures in the PP cohort were 31.0% and 15.5%, respectively (95% Cl of difference (15.5%): 3.2%-27.7%, P = 0.018). The benefit of omeprazole in the PP cohort was confirmed by secondary endpoints such as, no dyspeptic symptoms on the last 2 days of treatment and overall treatment response. H. pylori status and the level of oesophageal acid exposure did not significantly influence the response to therapy.

A subset of patients with FD will respond to therapy with omeprazole.