Impact of Baseline Heart Failure Burden on Post-Implantable Cardioverter-Defibrillator Mortality Among Medicare Beneficiaries
Does heart failure (HF) burden impact overall survival in patients undergoing implantation of an implantable cardioverter-defibrillator (ICD)?
This was a retrospective study of prospectively collected data from the Centers for Medicare and Medicaid Services ICD registry and the Medicare files. Patients ≥66 years old with an ejection fraction ≤35% who were undergoing primary prevention ICD implant were identified and then stratified by HF burden (defined as number of HF hospitalizations coded prior to ICD implant and the length of hospitalization during index ICD stay). Crude all-cause mortality was estimated based on HF burden.
There were 66,974 ICD recipients identified (mean age 75 years). Of these, 37% were New York Heart Association (NYHA) class I/II, 58% were NYHA class III, and 5% were NYHA class IV. Twenty-one percent of patients (n = 14,011) had had at least one HF hospitalization in the year prior to ICD implant, and 11% (n = 1,263) of the hospitalized patients had had ≥3 HF admissions. There were 11,876 deaths (31%; 3-year mortality). In those without prior HF hospitalizations, 3-year mortality was significantly lower (27%) compared with those with ≥3 prior HF hospitalizations (n = 63%; adjusted hazard ratio [HR], 1.8; 95% confidence interval [CI], 1.6-2.0). Mortality at 3 years in patients (n = 4,803, 6%) with >7 days of hospitalization prior to ICD implant was 53% compared with 25% in those (n = 39576, 59%) with <1 day of hospitalization (HR, 1.9; 95% CI,1.8-2.0).
The authors concluded that Medicare ICD recipients had higher overall mortality than prior ICD clinical trials. The benefit of ICD therapy in older patients with high HF burden is unclear.
Current American College of Cardiology/American Heart Association/Heart Rhythm Society ICD guidelines are asterisked with the phrase that ICD candidates should have a ‘reasonable expectation of survival with a good functional status for more than 1 year.’ While prior clinical trials demonstrated mortalities of 18-22%, Chen and colleagues identified nontrial ICD recipients who had much worse survival. Perhaps randomized studies using risk models (including the Seattle Heart Failure Model) to stratify patients for ICD candidacy by HF severity are warranted. Studies would also need to capture the burden of other comorbidities that may impact survival in the elderly.
Keywords: Comorbidity, Centers for Medicare and Medicaid Services (U.S.), Primary Prevention, Heart Diseases, Registries, Incidence, Clinical Coding, Heart Failure, Confidence Intervals, Defibrillators, Implantable, Death, Sudden, Cardiac
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