The effect of additional use of short-acting beta2 agonist on exercise tolerance in patients with COPD on regular long-acting bronchodilators treatments

Abstract

Background: Using short-acting beta2-agonists (SABA) before activities, referred to as “assist use” is reported to improve dyspnea and exercise tolerance in patients with chronic obstructive pulmonary disease (COPD), even if they regularly inhale long-acting bronchodilators. However, how much SABA assist use actually improve exercise tolerance is unclear. Objective: The purpose of this study was to examine the effect of SABA assist use on exercise tolerance in COPD patients. Methods: Patients with COPD (StageII-IV) who were regularly receiving inhaled long-acting bronchodilators treatments were enrolled. Incremental shuttle walking test (ISWT) was performed before and after SABA inhalation. Primary endpoint was the difference of walking distances before and after SABA inhalation. Observed difference was compared between the groups which were determined according to the long-acting bronchodilator regimen taken. Results: In 74 patients (average 72.4 years old, 71 male), mean baseline walking distances was 378.2m before SABA. After SABA inhalation it slightly but significantly increased to 384.7m (p=0.048). This effect was largest in long-acting muscarinic antagonists (LAMA) group (n=18) and mean walking distance was improved 14.4m after SABA inhalation but the difference was not significant (p=0.164). In long-acting beta2-agonists (LABA) group (n=26), the improvement was only 2.3m (p=0.406). In LAMA+LABA group (n=30), it was 5.3m (p=0.181). Among the groups, mean differences of walking distances were not significant. Conclusion: SABA assist use has only limited effects on exercise tolerance, which is assessed by ISWT, in COPD patients.