The relation between repeated 6-minute walk test performance and outcome in patients with chronic heart failure

Abstract

ObjectiveTo assess the prognostic implications of the 6-minute walk test (6-MWT) distance measured twice, one year apart, in a large sample of patients with chronic heart failure (CHF) followed for an extended period (>8years from baseline). Material and methodsPatients undertook a 6-MWT at baseline and at one year, and were followed up for 8years from baseline. ResultsSix hundred patients (median [inter-quartile range, IQR]) (age 78 [72–84] years; 75% males; body mass index 27 [25–31] kg·m−2; left ventricular ejection fraction 34 [26–38] %) were included. At baseline, median 6-MWT distance was 232 (60–386) m. There was no significant change in 6-MWT distance at one year (change −12m; P=0.533). During a median follow-up of 8.0years in survivors, 396 patients had died (66%). Four variables were independent predictors of all-cause mortality in a multivariable Cox model (adjusted for body mass index, age, QRS duration, left ventricular ejection fraction); increasing NT pro-BNP, decreasing 6-MWT distance at 1year, decreasing haemoglobin, and increasing urea. ConclusionsDistance walked during the 6-MWT is an independent predictor of all-cause mortality in patients with CHF. In survivors, the 6-MWT distance is stable at 1year. The 6-MWT distance at 1year carries similar prognostic information.