Study objectives: To determine the prevalence of gastroesophageal reflux disease (GERD)—both symptoms and objective evidence—using 24-h dual-probe pH monitoring in difficult asthma, and the relationship between the presence and treatment of GERD to clinical outcome.
Design and setting: As part of a systematic evaluation protocol, 68 subjects with difficult-to-control asthma attending a difficult asthma clinic were referred for dual-probe ambulatory pH esophageal monitoring.
Results: Esophageal probe data were available in 52 patients (76%) with difficult asthma. The prevalence of GERD/GERD-associated asthma symptoms was 75% (39 of 52 patients; 95% confidence interval [CI], 63 to 84.7%). The prevalence of GERD as evidenced by an abnormal pH profile at the distal esophageal probe was 55% (29 of 52 patients; 95% CI, 40 to 69%). The prevalence of GERD at the proximal probe was 34.6% (18 of 52 patients; 95% CI, 23.6 to 51%). The prevalence of GERD was similar in asthmatic subjects who responded to intervention and those who remained difficult to control (therapy resistant). Asymptomatic GERD was present in 9.6% (5 of 52 patients); 16% of cough episodes correlated with acid reflux.
Conclusions: In difficult-to-control asthma, GERD is common, but identification and treatment of GERD do not appear to relate to improvement in asthma control in this population.