Objective: To determine whether peak oxygen consumption (V̇o2peak) 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 V̇o2peak in predicting physical function and quality of life after accounting for FEV1.
Results: After accounting for FEV1, V̇o2peak added significantly to the prediction of 6-min walk distance (R2 increased by 0.395 [p < 0.005]); stair climb time (R2 increased by 0.262 [p < 0.005]); self-reported function (R2 increased by 0.109 [p < 0.005]); and health-related quality-of-life domain of mastery (R2 increased by 0.044 [p < 0.005]). Only V̇o2peak was found to significantly predict the health-related quality-of-life domain of fatigue (R2 = 0.094 [p < 0.005]).
Conclusion: After controlling for FEV1, V̇o2peak 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 V̇o2peak in the multidimensional assessment of COPD patients.