Abstract

Introduction: There are currently few studies in the literature that have sought to investigate whether functional performance measured by the distance covered in the six-minute walk test (6MWT) may be an important predictor of mortality in a broad spectrum of severity of chronic obstructive pulmonary disease (COPD). Objectives: To evaluate the functional capacity through the 6MWT considering the performance obtained in three quartiles of distance walked; and to verify the functional impact as predictors of survival in a 24-month follow-up in COPD patients. Methods: This is a 24-month cohort study, in which 118 patients with COPD were evaluated. The groups were stratified according to the distance covered in 6MWT: group 1 (n=39, mean 485-371m); group 2 (n=39, mean 370-260m) and group 3 (n=40, mean >259m). Results: The distance covered stratified according to functional performance, proved to be predictive of survival in COPD patients. In the Kaplan-Meier survival analysis, the patients over 24 months who had a 6MWT performance lower than <259m were those with the lowest probability of survival (log rank, p=0.001) and more symptomatic patients according to the COPD Assessment Test (CAT) presented worse performance in the 6MWT. Among the correlations obtained, poor performance in the 6MWT was associated with a higher CAT score (R= -0.344, p<0.001). Forced expiratory volume in 1 second was positively correlated with 6MWT performance (R=0.319 and p=0.001). Conclusions: The 6MWT has a predictive value of 24-months mortality, considering a wide spectrum of COPD severity. Distance walked was also closely associated with greater disease severity and worse CAT scores.