A prospective evaluation of esophageal testing and a double-blind, randomized study of omeprazole in a diagnostic and therapeutic algorithm for chronic cough

OBJECTIVE: Recent studies suggest an association between chronic cough and gastroesophageal reflux. Our study aims were 1) to define the prevalence of acid reflux induced cough in the general community, 2) to examine the abil ity of esophageal testing to identify gastroesophageal reflux related cough , and 3) to assess the utility of omeprazole in a chronic cough algorithm. METHODS: Patients with chronic cough of unknown etiology, who were mostly f rom the community, were evaluated. Subjects underwent a chest x-ray, methac holine challenge test, and empiric trial of postnasal drip therapy, and com pleted daily cough symptom diaries subjectively evaluating cough frequency and severity on a graded scale of 0-4 (combined maximum 8). After excluding other causes of cough, the remaining patients underwent esophageal and pH testing. Those testing positive were randomized to omeprazole 40 mg b.i.d. or placebo for 12 weeks. Follow-up was 1 yr. RESULTS: A total of 71 patients were screened; 48 were excluded. Twenty-thr ee patients were evaluated for gastroesophageal reflux disease; six (26%) w ere eventually determined to have an acid-related cough. Of these patients, 17 had a positive pH test, six (35%) of whom showed a striking improvement or resolution of their cough during omeprazole treatment which was sustain ed for up to 1 yr. Six had a negative pH test, none of whom responded to om eprazole therapy. No significant differences were seen between re spenders (n = 6) and nonresponders (n = 11) for demographic factors, baseline sympto m frequency and duration, or physiological parameters (motility/pH). CONCLUSIONS: Acid-related chronic cough was present in 26% (six of 23) of p atients evaluated for gastroesophageal reflux disease. Esophageal testing d oes not reliably identify patients with acid induced chronic cough responsi ve to proton pump inhibitor therapy. We suggest that the best diagnostic an d therapeutic approach, after excluding asthma and postnasal drip syndrome, is empiric treatment for 2 wk with a high dose proton pump inhibitor. (C) 1999 by Am. Cell. of Gastroenterology.