Chronic obstructive pulmonary disease surveillance - United States, 1971-2000

Problem/condition: Chronic obstructive pulmonary disease (COPD) includes chronic bronchitis and emphysema but has been defined recently as the physiologic finding of nonreversible pulmonary function impairment. This surveillance summary reports trends in different measures of COPD during 1971-2000.

Reporting period covered: This report presents national data regarding objectively determined COPD (1971-1994); COPD-associated activity and functional limitations (1980-1996); self-reported COPD prevalence, COPD physician office and hospital outpatient department visits, COPD hospitalizations, and COPD deaths (1980-2000); and COPD emergency department visits (1992-2000).

Description of systems: CDC's National Center for Health Statistics (NCHS) conducts the National Health Interview Survey annually, which includes questions concerning COPD and activity limitations. NCHS collects physician office-visit data in the National Ambulatory Medical Care Survey, emergency department and hospital outpatient department data in the National Hospital Ambulatory Medical Care Survey, hospitalization data in the National Hospital Discharge Survey, and death data in the Mortality Component of the National Vital Statistics System. Data regarding pulmonary function were obtained from the National Health and Nutrition Examination Surveys (NHANES) I (1971-1975) and III (1988-1994), and data regarding functional limitation were obtained from NHANES III, Phase 2 (1991-1994).

Results: During 2000, an estimated 10 million U.S. adults reported physician-diagnosed COPD. However, data from NHANES III estimate that approximately 24 million U.S. adults have evidence of impaired lung function, indicating that COPD is underdiagnosed. During 2000, COPD was responsible for 8 million physician office and hospital outpatient visits, 1.5 million emergency department visits, 726,000 hospitalizations, and 119,000 deaths. During the period analyzed, the most substantial changes was the increase in the COPD death rate for women, from 20.1/100,000 in 1980 to 56.7/100,000 in 2000, compared with the more modest increase in the death rate for men, from 73.0/100,000 in 1980 to 82.6/100,000 in 2000. In 2000, for the first time, the number of women dying from COPD surpassed the number of men dying from COPD (59,936 versus 59,118). Another substantial change observed is that the proportion of the population aged < 55 years with mild or moderate COPD, on the basis of pulmonary function testing, decreased from 1971-1975 to 1988-1994, possibly indicating that the upward trends in COPD hospitalizations and mortality might not continue.

Interpretation: COPD is a major cause of morbidity, mortality, and disability in the United States. Despite its ease of diagnosis, COPD remains an underdiagnosed disease, chiefly in its milder and more treatable form.