Impact of Baseline Heart Failure Burden on Post-Implantable Cardioverter-Defibrillator Mortality Among Medicare Beneficiaries

Objectives This study sought to assess the impact of baseline heart failure (HF) burden on survival with primary implantable cardioverter-defibrillator (ICD) among Medicare recipients. Background Survival after primary ICD implantation may differ between trial and Medicare populations. Methods Linking data from the CMS (Centers for Medicare and Medicaid Services) ICD registry and the Medicare files (2005 to 2009), we identified primary ICD recipients age >= 66 years with ejection fraction <= 35%. Number of previous HF hospitalizations (prev-HF-hosp) and length of hospitalization prior to implantation were used to define HF burden. Crude all-cause mortality was estimated. Adjusted hazard ratios (HR) were derived from Cox models. Results Of 66,974 ICD recipients (73% men, 88% white, mean age 75 years), 11,876 died (average follow-up = 1.4 years), with 3-year mortality of 31%. Among patients with no prev-HF-hosp, 3-year mortality was 27% compared with 63% in those with >= 3 prev-HF-hosp (adjusted HR: 1.8). Among patients with same-day implantation, 3-year mortality was 25% compared with 53% in those with >1-week hospitalization days prior to implantation (adjusted HR: 1.9). Mortality at 3-year follow-up among the 31,685 ICD recipients with no prev-HF-hosp and sameday implantation (low HF burden) was similar to that in trials (22%). Conclusions Nearly one-third of Medicare ICD recipients died within 3 years, reflecting a population with more advanced age and disease than seen in trial populations for primary prevention ICD. Nearly one-half of Medicare recipients had a low HF burden and had a survival similar to trial ICD recipients. Future research is warranted to understand the effectiveness of primary ICD implantation among Medicare beneficiaries with heavy HF burdens. (C) 2013 by the American College of Cardiology Foundation