Prognostic implications of six-minute walking distance in patients with heart failure with preserved ejection fraction

BACKGROUND:The incremental prognostic value of the six-minute walking test over conventional risk factors has not been evaluated in an adequate number of patients with heart failure with preserved ejection fraction (HFpEF). Therefore, we aimed to examine its prognostic significance using data from the FRAGILE-HF study. METHODS AND RESULTS:A total of 513 older patients who were hospitalized for worsening heart failure were examined. Patients were classified according to the tertiles of six-minute walking distance (6MWD): T1 (<166 m), T2 (166-285 m), and T3 (≥285 m). During the 2-year follow-up period after discharge, 90 all-cause deaths occurred. Kaplan-Meier curves showed that the T1 group had significantly higher event rates than the other groups (log-rank p = 0.007). Cox proportional hazard analysis revealed that the T1 group was independently associated with lower survival, even after adjusting for conventional risk factors (T3: hazard ratio 1.79, 95% confidence interval 1.02-3.14, p = 0.042). The addition of the 6MWD to the conventional prognostic model showed a statistically significant incremental prognostic value (net reclassification improvement 0.27, 95% confidence interval 0.04-0.49; p = 0.019). CONCLUSIONS:The 6MWD is associated with survival in patients with HFpEF and has an incremental prognostic value over conventional well-validated risk factors.