Background: We sought to evaluate the prognostic value of the 6-minute walk test in stable outpatients with heart failure.
Methods and results: We examined the association of 6-minute walk test distance and outcomes among 541 patients enrolled in the Digitalis Investigation Group trial. Patients were grouped by total distance (< or =200 m, 201 m-300 m, 301 m-400 m, and >400 m) with median follow-up of 32 months. All-cause mortality for patients who walked < or =200 m was significantly higher than patients who walked >200 m (43.9% versus 23.3%, P<0.001), but mortality was comparable among patients who walked >200 m (201 m-300 m: 23.7%, 301 m-400 m: 25.2%, >400 m 19.8%, P for trend 0.45). Results were similar for death due to worsening heart failure (< or =200 m: 29.3%, 201 m-300 m: 7.6%, 301 m-400 m: 6.7%, >400 m: 6.1%, P for trend <0.001). In multivariable analysis, distance < or =200 m remained associated with increased mortality (< or =200 m: hazard ratio (HR) 1.47, 95% CI 0.96-2.27; >200 m: HR 1.00, Referent; P=0.07) and death due to worsening heart failure (< or =200 m: HR 2.89, 95% CI 1.54-5.41; >200 m: 1.00, Referent; P=0.001).
Conclusions: The 6-minute walk test identifies patients who walk less than 200 m as being at markedly increased risk of death. Changing the 6-minute walk test to a time- and distance-based standard would improve the efficiency of the test while retaining the bulk of the prognostic information.