A comparison of three multidimensional indices of COPD severity as predictors of future exacerbations

Abstract

Background: Prediction of future exacerbations of chronic obstructive pulmonary disease (COPD) is a major concern for long-term management of this disease. Aim: To determine which of three multidimensional assessment systems (the body mass index, obstruction, dyspnea, and exercise capacity [BODE] index; dyspnea, obstruction, smoking, exacerbations [DOSE] index; or age, dyspnea, obstruction [ADO] index) is superior for predicting exacerbations. Methods: This was a 2-year prospective cohort study of COPD patients. Pulmonary function tests, the 6-minute walk distance (6MWD), Modified Medical Respiratory Council (MMRC) dyspnea scores, chest computed-tomography measurements, and body composition were analyzed, and predictions of exacerbation by the three assessment systems were compared. Results: Among 183 patients who completed the study, the mean annual exacerbation rate was 0.57 events per patient year, which correlated significantly with lower predicted forced expiratory volume in 1 second (FEV1) (P < 0.001), lower transfer coefficient of the lung for carbon monoxide (%DLco/VA) (P = 0.021), lesser 6MWD (P = 0.016), higher MMRC dyspnea score (P = 0.001), higher DOSE index (P < 0.001), higher BODE index (P = 0.001), higher ADO index (P = 0.001), and greater extent of emphysema (P = 0.002). For prediction of exacerbation, the areas under the curves were larger for the DOSE index than for the BODE and ADO indices (P < 0.001). Adjusted multiple logistic regression identified the DOSE index as a significant predictor of risk of COPD exacerbation. Conclusion: In this study, the DOSE index was a better predictor of exacerbations of COPD when compared with the BODE and ADO indices. © 2013 Motegi et al, publisher and licensee Dove Medical Press Ltd.