Abstract 10119: Cardio-respiratory Fitness and Incident Heart Failure
Aims: To asses the association between cardiorespiratory fitness (CRF) and risk of incident heart failure (HF).
Methods: Cardiorespiratory fitness, as measured by maximal oxygen uptake (VO2max), was assessed at baseline in a prospective cohort of 1,873 men aged 42-61 years without HF or chronic respiratory disease.
Results: During a mean follow-up of 20.4 years, 152 incident HF events were recorded. Within-person variability in levels of CRF calculated using data from repeat measurements taken 11 years apart was 0.58 (95% CI 0.52-0.64). Cumulative hazard curves demonstrated a greater risk of new-onset HF in the bottom quartile of CRF levels compared to those in the top quartile (P-value <0.001: Figure 1). The age-adjusted hazard ratio (HR) per unit increase (1 ml/kg/min of VO2max) in long term average levels of CRF was 0.89 (95% CI: 0.86 to 0.93), which was minimally attenuated to 0.93 (95% CI: 0.89 to 0.97) after further adjustment for established HF risk factors (systolic blood pressure, history of cardiovascular disease, diabetes, heart rate, and left ventricular hypertrophy) and incident coronary events as a time varying covariate. In a comparison of extreme quartiles of CRF levels (VO2max ≥ 35.4 vs. ≤ 25.7 ml/kg/min), the corresponding HRs were 0.27 (0.15 to 0.50) and 0.41 (0.22 to 0.75) respectively. Each 1-MET (metabolic equivalent of oxygen consumption) increment in CRF was associated with a 25% (12-35%) reduction in multivariable adjusted risk of HF. Addition of CRF to a HF risk prediction model containing established risk factors did not significantly improve risk discrimination (C-index change=0.0164, P=0.07).
Conclusions: There is a strong, inverse, and independent association between long-term CRF and HF risk, consistent with a dose-response relationship. The protective effect of CRF on HF risk should be evaluated in larger studies.
- © 2013 by American Heart Association, Inc.