The Global Initiative on Obstructive Lung Disease stages for chronic obstructive pulmonary disease (COPD) uses a fixed ratio of the post-bronchodilator forced expiratory volume in 1 second (FEV(1))/forced vital capacity (FVC) of 0.70 as a threshold. Since the FEV(1)/FVC ratio declines with age, using the fixed ratio to define COPD may "overdiagnose" COPD in older populations.
Division of Pulmonary and Critical Care Medicine, University of Kentucky Medical Center, 740 S Limestone, K-528, Lexington, KY 40536, USA. dmannino@uky.edu
