Systematic review and meta-analysis of randomised controlled trials of gastro-oesophageal reflux interventions for chronic cough associated with gastro-oesophageal reflux.

OBJECTIVE To evaluate the efficacy of treatment for gastro-oesophageal reflux disease (GORD) on chronic cough in children and adults without an underlying respiratory disease. DESIGN Systematic review and meta-analysis. DATA SOURCES Cochrane, Medline, and Embase databases, references from review articles. INCLUDED STUDIES Randomised controlled trials on GORD treatment for cough in children and adults without primary lung disease. Two reviewers independently selected studies and extracted paediatric and adult data on primary (clinical failure) and secondary outcomes. RESULTS 11 studies were included. Meta-analysis was limited to five studies in adults that compared proton pump inhibitors with placebo. All outcomes favoured proton pump inhibitors: the odds ratio for clinical failure (primary outcome) was 0.24 (95% confidence interval 0.04 to 1.27); number needed to treat (NNT) was 5 (harm 50 to infinity to benefit 2.5). For secondary outcomes, the standardised mean difference between proton pump inhibitors and placebo was -0.51 (-1.02 to 0.01) for mean cough score at the end of the trial and -0.29 (-0.62 to 0.04) for change in cough score at the end of the trial. Subgroup analysis with generic inverse variance analysis showed a significant mean change in cough (-0.41 SD units, -0.75 to -0.07). CONCLUSION Use of a proton pump inhibitor to treat cough associated with GORD has some effect in some adults. The effect, however, is less universal than suggested in consensus guidelines on chronic cough and its magnitude of effect is uncertain.