Prognostic impact of 6 min walk test distance in patients with systolic heart failure: insights from the WARCEF trial

Aims This study aimed to investigate the impact of baseline 6 min walk test distance (6MWTD) on time to major cardiovascular (CV) events in heart failure with reduced ejection fraction (HFrEF) and its impact in clinically relevant subgroups. Methods and results In the WARCEF (Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction) trial, 6MWTD at baseline was available in 2102 HFrEF patients. Median follow-up was 3.4 years. All-cause death and heart failure hospitalization (HFH) exhibited a significant non-linear relationship with 6MWTD (P = 0.023 and 0.032, respectively), whereas a significant association between 6MWTD and CV death was shown in a linear model [hazard ratio (HR) per 10 m increase, 0.989; P = 0.011]. In linear splines with the best cut-off point at 200 m, the positive effect of a longer 6MWTD on all-cause death and HFH was only observed for 6MWTD > 200 m (HR per 10 m increase, 0.987; P = 0.0036 and 0.986; P = 0.0022, respectively). The associations between 6MWTD and CV outcomes were consistent across clinical subgroups; for age, a significant relationship between 6MWTD and HFH was observed in patients >= 60 years (HR per 10 m increase, 0.98; P < 0.001), but not in patients <60 years (HR per 10 m increase, 1.00; P = 0.98; P = 0.02 for the interaction). Conclusions In HFrEF, 6MWTD is independently associated with all-cause death, CV death, and HFH. 6MWTD of 200 m is the best cut-off point for predicting these adverse events. The prognostic impact of 6MWTD for HFH was only observed in older patients.