Association of six-minute walk distance (6MWD) with resting pulmonary function in patients with chronic obstructive pulmonary disease (COPD).

BACKGROUND: The six-minute walk test (6MWT) is widely used for integrated assessment of patients with chronic obstructive pulmonary disease (COPD). However, little is known concerning which resting pulmonary function test measurements relate to six-minute walk distance (6MWD).

METHODS: We retrospectively analyzed consecutive data of spirometry, lung volume analysis, and measurements of diffusing capacity of the lung for carbon monoxide (DLCO) and 6MWT from total of one-hundred and thirty patients with COPD. Univariate and multivariate analyses were performed to examine the relationships between 6MWD and variables.

RESULTS: By linear regression analysis, 6MWD was significantly associated with age, weight, BMI, FEV1.0, FEV1.0 (% predicted), IC, TLC, IC/TLC, FEF25-75, DLCO (% predicted), and DLCO/VA. Stepwise multiple regression analysis revealed that age (r2 = 0.173; p < 0.0001), IC (r2 = 0.18; p < 0.0001), and DLCONA (r2 = 0.238; p < 0.0001) significantly accounted for 6MWD.

CONCLUSIONS: The present results suggest that age, IC, and DLCONA were significantly associated with 6MWD in patients with COPD.