Outcomes in African Americans undergoing cardioverter-defibrillator implantation for primary prevention of sudden cardiac death: Findings from the Prospective Observational Study of Implantable Cardioverter-Defibrillators (PROSE-ICD)

Background Implantable cardioverter-defibrillators (ICDs) reduce the risk of death in patients with left ventricular dysfunction. Little is known regarding the benefit of this therapy in African Americans (AAs). Objective The purpose of this study was to determine the association between AA race and outcomes in a cohort of primary prevention ICD patients. Methods We conducted a prospective cohort study of patients with systolic heart failure who underwent ICD implantation for primary prevention of sudden cardiac death. The primary end-point was appropriate ICD shock defined as a shock for rapid ventricular tachyarrhythmias. The secondary end-point was all-cause mortality. Results There were 1189 patients (447 AAs and 712 non-AAs) enrolled. Over a median follow-up of 5.1 years, a total of 137 patients experienced an appropriate ICD shock, and 343 died (294 of whom died without receiving an appropriate ICD shock). The multivariate adjusted hazard ratio (95% confidence interval) comparing AAs vs non-AAs were 1.24 (0.96-1.59) for all-cause mortality, 1.33 (1.02, 1.74) for all-cause mortality without receiving appropriate ICD shock, and 0.78 (0.51, 1.19) for appropriate ICD shock. Ejection fraction, diabetes, and hypertension appeared to explain 24.1% (10.1%-69.5%), 18.7% (5.3%-58.0%), and 13.6% (3.8%-53.6%) of the excess risk of mortality in AAs, with a large proportion of the mortality difference remaining unexplained. Conclusion In patients with primary prevention ICDs, AAs had an increased risk of dying without receiving an appropriate ICD shock compared to non-AAs.