Abstract 13154: Benefit Of Exercise Training Independent Of Heart Failure Severity: The HF-action Experience
Background: The Heart Failure and A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) Study identified a modest benefit of exercise training (ET) in HF subjects. We undertook this post-hoc analysis to evaluate if there was a differential effect of ET based on HF severity.
Methods: HF-ACTION was a randomized controlled trial evaluating the impact of ET relative to usual care (UC) alone in patients with LV function ≤ 35% treated with evidence-based HF medical therapy. This analysis uses three criteria for severity: risk score derived from a predictive model based on HF ACTION data, NYHA class and cardiopulmonary exercise test (CPX) duration. Primary analysis used the risk score. To test impact of treatment on endpoints among different severity groups, the interaction between treatment and severity variable was examined in a survival model (unadjusted). The outcomes evaluated were all-cause mortality or all-cause hospitalization (primary), cardiovascular (CV) mortality or CV hospitalization, CV mortality or HF hospitalization, and all-cause mortality.
Results: Due to missing data in variables deriving the risk score, 1775 subjects were included in the analysis. In the primary analysis with predictive model risk score as a continuous variable and in the secondary analysis using NYHA class, the interaction terms were non-significant for the primary endpoint and for the prespecified secondary endpoints. When severity was evaluated as CPX duration, there was a significant interaction between CPX duration and treatment arm for the primary endpoint.(p=0.03) Among persons with CPX duration less than the median there was a significant reduction in the primary endpoint with ET compared with UC (70.3% vs. 75.4%) in contrast to persons with CPX duration equal to or greater than the median (ET 48.1% vs. UC 48.2%). There was no significant interaction between treatment and CPX time for secondary endpoints.
Conclusion: Within the HF-ACTION study, the modest benefit of exercise training was similar irrespective of risk score or NYHA class. However, subjects with CPX duration below the median did have a greater benefit from exercise training (vs. UC) for the primary outcome of the study but this finding was not identified for secondary endpoints.
- © 2010 by American Heart Association, Inc.