COPD - You've heard of it, but what is it really? COPD stands for Chronic Obstructive Pulmonary Disease. Its more common than you think. According to the Center for Disease Control, in 2011, 12.7 million U.S. adults (aged 18 and over) were estimated to have COPD. However, close to 24 million U.S. adults have evidence of impaired lung function, indicating an under diagnosis of COPD. Moreover, COPD is the third leading cause of death in America.