The 6-Min Walk Distance, Peak Oxygen Uptake, and Mortality in COPD

Cote CG, Pinto-Plata V, Kasprzyk K, Dordelly LJ, Celli BR

This study compared the association between the 6-min walk distance (6MWD) and the maximal oxygen uptake (peak VO2) and mortality in 365 patients with COPD between 1994 and 2005. Patients included in the study had a: smoking history > 10 pack-years; diagnosis of COPD; FEV1/FVC ratio of, 0.7; response to bronchodilator of 12% or 200mL. They had all been clinically stable for 6 weeks prior to entry into the study. The cardiopulmonary exercise test (cycle ergometry) and 6MWD were performed on different days.

No significant difference was found between the survival of patients walking > 350m and achieving >41% of their predictive value for peak VO2 (survival rate 65%). Survival of patients walking < 350m was 39%, while those walking < 250m had a 5 year survival rate of 26%. The study showed somewhat surprisingly that the 6MWD performed as well if not better than the peak VO2 in predicting mortality in the above cohort.

Chest 2007; 132 (6):1778-1785

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