Association of improvement in functional capacity after rehabilitation with long-term survival in heart failure

Abstract

Background: The prognostic value of change in six-minute walking distance (6MWD) after treatment to predict mortality in heart failure (HF) remains a controversial issue. We assessed the prognostic value of rehabilitation-induced improvement in 6MWD in predicting mortality in patients with HF.

Methods: We studied 2257 patients admitted to six inpatient rehabilitation facilities after a hospitalization for HF (N. 912) or because of worsening functional capacity and/or deteriorating clinical status (N. 1345). A six-minute walking test was performed at admission and discharge. The primary outcome was 3-year all-cause mortality after discharge from cardiac rehabilitation. We used multivariable Cox proportional hazard modeling to assess the association of increase in 6MWD with 3-year mortality, adjusting for established predictors of mortality.

Results: 6MWD significantly increased by 61 m (p < .001) from admission to discharge and 969 patients (42.9%) achieved an increase in 6MWD >50 m. After full adjustment, an increase in 6MWD >50 m was associated with a 22% decreased risk for 3-year mortality (HR 0.78 [95% CI 0.68-0.91]; p = .002). When modeled as a continuous variable, improvement in 6MWD remained independently associated with decreased risk for 3-year mortality (HR per each 50 m increase: 0.92 [95% CI 0.88-0.96]).

Conclusions: Rehabilitation-induced improvement in 6MWD was associated with a significantly reduced risk for 3-year mortality. Our data also suggest that an improvement in 6MWD of more than 50 m could represent a clinically meaningful endpoint of cardiac rehabilitation for patients with heart failure.

Keywords: Cardiac rehabilitation; Heart failure; Prognosis; Six-minute walking test.