The Body-Mass Index, Airflow Obstruction, Dyspnea, and Exercise Capacity Index in Chronic Obstructive Pulmonary Disease

Although the primary physiological abnormality in chronic obstructive pulmonary disease (COPD) is airway obstruction, extrapulmonary manifestations of COPD also contribute to the risk of death. The authors of this study devised a novel index based on body-mass index, the forced expiratory volume in one second, the distance walked in six minutes, and the patient's perceived level of dyspnea. Body-mass index, forced expiratory volume, distance walked, and level of dyspnea can predict the risk of death. Chronic obstructive pulmonary disease (COPD), a common disease characterized by a poorly reversible limitation in airflow, 1 is predicted to be the third most frequent cause of death in the world by 2020. 2 The risk of death in patients with COPD is often graded with the use of a single physiological variable, the forced expiratory volume in one second (FEV 1 ). 1 , 3 , 4 However, other risk factors, such as the presence of hypoxemia or hypercapnia, 5 , 6 a short distance walked in a fixed time, 7 a high degree of functional breathlessness, 8 and a low body-mass index (the weight in kilograms divided . . .