Efficacy of omeprazole on cough, pulmonary function and quality of life of patients with sulfur mustard lung injury: A placebo-control, cross-over clinical trial study

BACKGROUND: Gastro-esophageal reflux disease (GERD) is prevalent and related to more severe disease in patients with respiratory problems. We evaluated the effects of antireflux therapy in warfare victims of exposure to Mustard gas with chronic cough. MATERIALS AND METHODS: This randomized, double-blind, placebo-controlled, cross-over study was conducted on 45 cases of sulfur mustard injury with chronic cough (≥8 weeks) and GERD. Patients were randomized into two groups, receiving either 20 mg twice daily omeprazole-placebo (OP) or matching placebo (placebo-omeprazole [PO]) for 4 months, followed by a 1-month washout period and the alternative treatment for 4 months. Assessments included GERD and cough, quality of life, and pulmonary function using spirometry. Leicester Cough Questionnaire and SF-36 were used for measuring quality of life. RESULTS: Patients in the OP group experienced a more decrease than those in the PO group in severity of Leicester cough scores during the first 4-month of trial. After crossing the groups, the OP group experienced an increase (P = 0.036) and the PO group experienced a nonsignificant decrease (P = 0.104) in the severity of scores. The OP group also experienced improvement in GERD symptoms and quality of life at the end of the trial, but changes in the PO group was not significant. There was no significant change in respiratory function indices in any groups. CONCLUSION: Long-term treatment with high-dose omeprazole improved GERD as well as cough, and quality of life, but not changed respiratory function indices in sulfur mustard injured cases with respiratory symptoms.