Is an anticholinergic agent superior to a β₂-agonist in improving dyspnea and exercise limitation in COPD?

Study objective: To evaluate the impact of a week-long course of inhaled albuterol compared with ipratropium on expiratory peak flow, exercise performance, and dyspnea in patients with stable COPD. Design and interventions: A double-blind, two-period, crossover evaluation, wherein the subjects inhaled albuterol, two puffs four times a day (qid) for 7 days, or ipratropium, two puffs qid for 7 days, in random sequence. Setting: Outpatients of the Pennsylvania State University Hospital, Lebanon VA Medical Center, and local private office practices. Participants: A sample of 15 subjects with stable COPD with FEV₁ <55% predicted. Measurements and results: Variables measured at baseline (no inhaled bronchodilator) and/or on day 7 of each arm included FEV₁ (liters), 12-min walk test distance (meters), 'rescue' puffs of metaproterenol needed each week, and dyspnea scoring after walking, on the Borg Category Scale (0 to 10=maximal). There was no significant difference in distance walked in 12 min (mean of 751.0±55.5 [±SE]) vs 755.7±61.3 m) or perceived dyspnea (mean 2.7±0.4 vs 3.3±0.4) during albuterol or ipratropium use. Seven patients preferred ipratropium, seven preferred albuterol, and one had no preference. Conclusion: We conclude that the effects of 1 week of albuterol or ipratropium have similar effects on exercise performance and subjective dyspnea in patients with stable COPD.