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.