A systematic review of the effects of bronchodilators on exercise capacity in patients with COPD

One of the major goals of bronchodilator therapy in patients with COPD is to decrease airflow limitation in the airways and, as a consequence, improve dyspnea and exercise tolerance. The focus of this systematic review is to assess the effects of treatment with beta-agonists, anticholinergics, and theophyllines on dyspnea, and steady-state and incremental exercise capacity. Thirty-three, double-blind, randomized, placebo-controlled studies written in English were selected. This review shows that approximately half of the studies showed a significant effect of bronchodilator therapy on exercise capacity. Anticholinergic agents have significant beneficial effects in the majority of studies, especially when measured by steady-state exercise protocols. There is a trend toward a better effect of high-dose compared to low-dose anticholinergics. Short-acting beta(2)-mimetics have favorable effects on exercise capacity in more than two thirds of the studies; surprisingly, the situation is less clear for long-acting beta(2)-agents. The majority of the results of the published reports on theophyllines and their effects on exercise are negative. Direct comparisons of different classes of bronchodilators have not been made in a sufficient number of studies for a rational preference. The addition of a second bronchodilator has no proven advantage for improving exercise test results, but this has not been studied extensively and not in sufficiently large studies. The majority of studies reporting a measure of dyspnea found improvements, even in the absence of improvement in exercise capacity.