Small Airways in COPD

Chronic obstructive pulmonary disease (COPD) is a major and growing global health problem. It ranked as the sixth most common cause of death worldwide in 1990, and the Global Burden of Disease Study predicted that it would become the third most common cause by 2020.1 COPD has already risen to fourth place and is the only common cause of death in the United States whose prevalence has increased over the past 20 years. Even more important, it is an increasingly common cause of chronic disability and is predicted to become the fifth most common cause of disability in the world . . .