Abstract 10990: Regulatory Implications of Different Definitions and Outcomes in Worsening Heart Failure

Introduction: Despite the use of different definitions for worsening heart failure (WHF) in prior clinical trials and registries, an in-hospital WHF event has consistently been associated with worse patient outcomes. WHF is being considered as a potential endpoint to support drug approval. We combined patients from two acute HF trials conducted by the HF Network (ROSE-AHF and DOSE-AHF) to understand how different WHF definitions are associated with event rates. Methods: WHF was defined as persistent or worsening HF requiring rescue therapy including IV vasoactive agents, ultrafiltration, or mechanical support over 72 hours after randomization in ROSE and also included additional open label loop or thiazide diuretic in DOSE. We assessed the relationship between WHF and the composite endpoint (CE) of re-hospitalization, emergency room visits for HF and mortality through 60 days. We also assessed for a differential relationship of WHF from 0-24 hours, 24-48 hours and 48-72 hours post-randomization. Results: The overall incidence of WHF was 14.6% (24.1% in DOSE and 6.3% in ROSE). Patients who developed WHF had lower baseline systolic blood pressure, less peripheral edema and higher BUN. In the combined dataset, WHF was associated with an increase in the CE (hazard ratio [HR] 1.64; 95% confidence interval [CI] 1.11-2.42; p-value 0.01). However, the association between WHF and 60-day outcomes was significant in ROSE but not in DOSE (Table). The development of WHF between 48-72 hours compared with 0-24 hours or 24-48 hours was associated with improved outcomes ([HR] 0.48, 95% CI 0.27 - 0.88, p-value 0.02 and [HR] 0.45, 95% CI 0.26 - 0.78, p-value 0.004, respectively). Conclusions: A WHF definition that incorporated intensification of diuretics increased the event rate but was not associated with worse 60-day outcomes. The timing of a WHF event also had a differential association with outcomes. These data support the use of a standardized WHF definition in clinical trials.