Randomised clinical trial: high-dose acid suppression for chronic cough - a double-blind, placebo-controlled study.

Aliment Pharmacol Ther 2011; 33: 225–234 Summary Background  Cough may be a manifestation of gastro-oesophageal reflux disease (GERD). The utility of acid suppression in GERD-related cough is uncertain. Aim  To assess the impact of high-dose acid suppression with proton pump inhibitors (PPI) on chronic cough in subjects with rare or no heartburn. Methods  Subjects were nonsmokers without history of asthma, with chronic cough for >8 weeks. All subjects underwent a baseline 24-h pH/impedance study, methacholine challenge test and laryngoscopy. Subjects were randomised to either 40 mg of esomeprazole twice daily or placebo for 12 weeks. The primary outcome measure was the Cough-Specific Quality of Life Questionnaire (CQLQ). Secondary outcomes were response on Fisman Cough Severity/Frequency scores and change in laryngeal findings. Results  Forty subjects were randomised (22 PPI, 18 placebo) and completed the study. There was no difference between PPI and placebo in CQLQ (mean improvement 9.8 vs. 5.9 respectively, P = 0.3), or Fisman Cough Severity/Frequency scores. Proportion of patients who improved by >1 s.d. on the CQLQ was 27.8% (five of 18) and 31.8% (seven of 22) in the placebo and PPI groups respectively. Conclusion  In subjects with chronic cough and rare or no heartburn, high-dose proton pump inhibitor does not improve cough-related quality of life or symptoms.