COPD exacerbations.

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the United States. It's estimated that more than 13 million U.S. adults have COPD, and as many as 24 million have evidence of impaired lung function, suggesting that COPD is underdiagnosed. Even when patients receive optimal COPD therapy, they periodically experience exacerbations, which reduce lung function and quality of life, increase risk of death from COPD, and account for the majority of costs related to COPD treatment. This article, the second in a two-part series on COPD, outlines current guidelines and evidence-based recommendations for identifying, assessing, and managing COPD exacerbations (the first article in the series, "An Evidence-Based Approach to COPD," March 2012, focused on the management of stable COPD in the outpatient setting).