title: No effect of omeprazole on pH of exhaled breath condensate in cough associated with gastro-oesophageal reflux.
abstract: BACKGROUND
  Endogenous airway acidification evaluated as pH in exhaled breath condensate (EBC) has been described in patients with chronic cough. Proton pump inhibitors improve gastro-oesophageal reflux (GOR)-associated cough.
  
  
  METHODS
  We examined pH levels in EBC and capsaicin cough response in 13 patients with chronic cough (mean age 41 years, SD 9) associated with GOR before and after omeprazole treatment (40 mg/day for 14 days) and its relationship with clinical response.
  
  
  RESULTS
  Omeprazole abolished symptoms associated with GOR. Patients with chronic cough had an EBC pH of 8.28 (SD 0.13) prior to treatment but this did not change with omeprazole treatment. There was a significant improvement in the Leicester Cough Questionnaire symptom scores from 80.8 points (SD 13.2) to 95.1 (SD 17) (p = 0.02) and in a 6-point scale of cough scores, but there was no change in capsaicin cough response.
  
  
  CONCLUSIONS
  An improvement in GOR-associated cough was not associated with changes in EBC pH or capsaicin cough response. These parameters are not useful markers of therapeutic response.
authors.affiliation: Department of Thoracic Medicine, National Heart & Lung Institute, Imperial College, Royal Brompton Hospital, London, UK. a.torrego@imperial.ac.uk
authors.forename: Alfonso
authors.initials: A
authors.lastname: Torrego
authors.forename: Stefan
authors.initials: S
authors.lastname: Cimbollek
authors.forename: Mark
authors.initials: M
authors.lastname: Hew
authors.forename: Kian Fan
authors.initials: KF
authors.lastname: Chung