Scope of the COPD problem in North America: early studies of prevalence and NHANES III data: basis for early identification and intervention.

COPD is a common disease that is often not diagnosed in the primary-care setting. This review highlights the findings of studies ranging from the early 1960s to the third National Health and Nutrition Examination Survey (NHANES III) study, undertaken to try and accurately estimate the prevalence of COPD in the US population. Results of the NHANES III indicate that COPD remains frequently underdiagnosed, and that spirometry should be more widely used in the primary-care setting to identify asymptomatic disease. Early intervention, in particular smoking cessation, could alter the course and outcome of disease in patients with COPD.