Systematic review and meta-analysis: proton pump inhibitors slightly decrease the severity of chronic cough

The Montreal consensus recognizes chronic cough as an extra-esophageal manifestation of gastroesophageal reflux disease. We performed a meta-analysis to assess the effects of acid-suppressive medications in adults with non-specific chronic cough. The protocol was registered on PROSPERO (CRD42022368769). Placebo-controlled randomized trials evaluating the impact of acid-suppressive medications on persistent cough were included. The systematic search was performed on the 1st of November 2022 in three databases. A random-effects model was used for the calculations. The effect size was the standardized mean difference (SMD) with 95% confidence interval (CI). A total number of 11 double-blinded placebo-controlled randomized trials were included in the meta-analysis. Data showed that compared to placebo, PPIs decreased the severity of cough (SMD 0.33; CI 0.05; 0.61). Therapeutic response was not different in patients with non-specific chronic cough only, compared to those with laryngopharyngeal reflux. Prolonged treatment durations did not result in greater symptomatic improvement, with SMD 0.33 (CI - 0.22; 0.88), 0.31 (CI - 1.74; 2.35), 0.32 (CI - 0.29; 0.93) and 0.34 (CI - 0.16; 0.85), following 4, 6, 8 and 12 weeks of treatment, respectively. The pooled analysis of the improvement in quality of life with PPIs found an SMD of 0.39 (CI - 0.51; 1.29). PPIs mildly decrease the severity of non-specific chronic cough, irrespective of treatment duration.