Use of peak oxygen consumption in predicting physical function and quality of life in COPD patients

Objective: To determine whether peak oxygen consumption (Vo(2)peak) adds to the power of FEV1 in predicting physical function and quality of life in COPD patients. Design: Single-center cross-sectional study. Methods: Subjects included 291 COPD patients who completed pulmonary function testing, a graded exercise test, a 6-min walk, and stair climb test to assess physical function; a questionnaire assessing self-reported physical function; and a disease-specific, health-related quality-of-life questionnaire. Hierarchical multiple regression analysis was used to determine the contribution of Vo(2)Peak in predicting physical function and quality of life after accounting for FEV1. Results: After accounting for FEV1, Vo(2)peak added significantly to the prediction of 6-min walk distance (R-2 increased by 0.395 [p < 0.005]); stair climb time (R-2 increased by 0.262 [p < 0.005]); self-reported function (R-2 increased by 0.109 [p < 0.005]); and health-related quality-of-life domain of mastery (R-2 increased by 0.044 [p < 0.005]). Only Vo(2)peak was found to significantly predict the health-related quality-of-life domain of fatigue (R-2 = 0.094 [p < 0.005]). Conclusion: After controlling for FEV1, Vo(2)Peak adds significantly to the prediction of physical function and health-related quality-of-life domain of mastery in COPD patients. These results provide additional support for the use of Vo2peak in the multidimensional assessment of COPD patients.