Dry and wet cough in children, as determined by clinicians and parents has good clinical validity. Clinicians should however be cognisant that children with dry cough may have minimal to mild airway secretions. Brassy cough determined by respiratory physicians is highly specific for tracheomalacia.

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 ∞ 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.

PPI is not efficacious for cough associated with GORD symptoms in very young children (including infants) and should not be used for cough outcomes. There is insufficient data in older children to draw any valid conclusions. In adults, there is insufficient evidence to conclude definitely that GORD treatment with PPI is universally beneficial for cough associated with GORD. Clinicians should be cognisant of the period (natural resolution with time) and placebo effect in studies that utilise cough as an outcome measure. Future paediatric and adult studies should be double-blind, randomised controlled and parallel-design, using treatments for at least two months, with validated subjective and objective cough outcomes and include ascertainment of time to respond as well as assessment of acid and/or non-acid reflux.