Drug Treatment for Early-Stage COPD.

Chronic obstructive pulmonary disease (COPD) is a common disease with an estimated global prevalence of 11.7%, affecting almost 400 million people around the world.1 In the United States, approximately 14% of adults 40 to 79 years of age have COPD.2 Although the prevalence of different stages of COPD as defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD)3 varies among different countries,4 early-stage COPD — stage 1 disease, a facet of which is a forced expiratory volume in 1 second (FEV1) of 80% or more of the predicted value, and stage 2 disease, which includes an FEV1 of . . .