Bolling‐Sternevald 2002

Methods	Setting: multicentre study in Denmark and Sweden. Design: double‐blind, placebo‐controlled RCT.
Participants	197 participants with recurrent symptoms (epigastric pain/discomfort) at least 1 month and normal OGD; HP+ were not excluded. Exclusions: people with predominant reflux or IBS symptoms.
Interventions	PPI: omeprazole 20 mg twice daily. Placebo. Duration: 2 weeks.
Outcomes	No epigastric pain on the last day of assessment. No dyspepsia symptoms on the last 2 days of assessment.
Notes	Funding by AstraZeneca.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomization list in blocks of 4 for each centre.
Allocation concealment (selection bias)	Unclear risk	No detailed information provided.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind study, personnel and participants blinded.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Double‐blind study, physicians and participants blinded throughout the study. It is likely that the outcome assessors (physicians) were also blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	6 participants in each group did not have complete outcome data; however, the number of participants and the reasons for incomplete outcome were balanced between the groups (PPI vs placebo: 0 vs 1 withdrawn, 2 vs 1 lost to follow‐up, 2 vs 3 discontinued treatment due to worsening symptoms, 2 vs 1 stopped treatment due to adverse events). It is unlikely to have impacted on the treatment effect estimates.
Selective reporting (reporting bias)	Low risk	Reported planned outcome data; however, no SD reported for quality scores, although mean scores and P values reported.
Other bias	Unclear risk	9 participants who did not fulfil the inclusion criteria were randomized by mistake, it is unclear whether these participants impacted on the treatment effect estimates.