The role of gastroesophageal reflux in exercise-triggered asthma: a randomized controlled trial.

BACKGROUND: Exercise-triggered asthma (ETA) develops when physical activity triggers asthma symptoms during or directly after exercise. In patients prone to symptoms of supra-esophageal reflux, exercise may trigger gastroesophageal reflux (GER), resulting in such symptoms. AIMS: To determine the prevalence of abnormal pH in patients with ETA and to determine whether acid suppression improves symptoms in ETA patients. METHODS: We performed a randomized double-blind trial of rabeprazole versus placebo in the treatment of patients with ETA. Patients underwent treadmill protocol to determine their VO(2 max). Next, pH testing was initiated while undergoing a 30-min treadmill program exercising them at 65% of their VO(2 max). They were subsequently randomized to rabeprazole or placebo for 10 weeks. At the end of 10 weeks, exercise testing was repeated. RESULTS: A total of 31 patients completed the study (20 asthmatics, 11 non-asthmatics). Twenty-two out of 30 (73%) subjects had abnormal pH studies. For all subjects, rabeprazole improved symptoms more than placebo (P = 0.03). The association was stronger in the pH-positive group (P = 0.009). CONCLUSION: Acid reflux is common in ETA patients. Many patients with exercise-related respiratory symptoms are misdiagnosed as chronic asthmatics. Exercise-related symptoms improve with the use of acid suppression. This study suggests that ETA patients may benefit from acid suppression.

Rates of hospitalizations and emergency department visits in patients with asthma and chronic obstructive pulmonary disease taking beta-blockers.

STUDY OBJECTIVE: To determine the rates of hospitalizations and emergency department (ED) visits during cardioselective and nonselective beta-blocker therapy in patients with asthma and/or chronic obstructive pulmonary disease (COPD). DESIGN: Retrospective, observational cohort study. DATA SOURCE: Electronic medical records database. PATIENTS: A total of 11,592 adult patients with asthma and/or COPD, identified from August 1, 1997-December 31, 2005, who were taking beta-blockers for at least 30 days or had never received a beta-blocker (controls). MEASUREMENTS AND MAIN RESULTS: Of these patients, 3062 were taking cardioselective and 690 nonselective beta-blockers; 7840 were controls. The primary end point for the beta-blocker groups was the rate of hospitalizations and ED visits/patient-year of beta-blocker therapy relative to the control group. In patients with asthma with or without concomitant COPD, cardioselective beta-blockers were associated with a relative risk of 0.89 (95% confidence interval [CI] 0.53-1.50) for hospitalizations and 1.40 (95% CI 1.20-1.62) for ED visits compared with controls. Nonselective beta-blockers were associated with a relative risk of 2.47 (95% CI 1.37-4.48) for hospitalizations and 1.21 (95% CI 0.91-1.62) for ED visits. In patients with COPD only, cardioselective beta-blockers were associated with a relative risk of 0.64 (95% CI 0.43-0.96) for hospitalizations and 1.19 (95% CI 1.02-1.39) for ED visits. Nonselective beta-blockers were associated with a relative risk of 1.02 (95% CI 0.52-2.02) for hospitalizations and 0.51 (95% CI 0.33-0.80) for ED visits. CONCLUSION: In patients with asthma with or without COPD, both cardioselective and nonselective beta-blocker use increased hospitalizations and ED visits compared with controls. Thus, these patients should receive beta-blocker therapy only if their cardiac risk exceeds their pulmonary risk and if they have concomitant cardiac disease for which beta-blockers decrease mortality, such as previous acute myocardial infarction or chronic heart failure. In patients with COPD only, cardioselective beta-blockers slightly increased the risk of ED visits but reduced the risk of hospitalizations. Nonselective beta-blocker therapy in these patients reduced the rate of ED visits and total visits. These findings suggest a larger safety margin with beta-blocker therapy in patients with COPD only than in those with asthma with or without COPD.