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)

Abstract

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 (AA). Objective To determine the association between African-American race and outcomes in a cohort of primary prevention cardioverter defibrillators (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 endpoint was appropriate ICD shock defined as a shock for rapid ventricular tachyarrhythmias. The secondary endpoint was all-cause mortality. Results There were 1,189 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 ratios (95% CI) comparing AAs vs. non-AAs were 1.24 (0.96 to 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 to 69.5%), 18.7% (5.3 to 58.0%), and 13.6% (3.8 to 53.6%) of the excess risk of mortality in AAs, with a large proportion of the mortality difference remains unexplained. Conclusions In patients with primary prevention ICDs, AAs had an increased risk of dying without receiving an appropriate ICD shock compared to non-AAs.

Racial and ethnic differences in implantable cardioverter-defibrillator patient selection, management, and outcomes

“… 31 , 32 , 33 The PROSE-ICD (Prospective Observational Study of Implantable Cardioverter-Defibrillators) study identified an increased risk of dying without receiving an appropriate ICD shock among Black recipients of a primary prevention ICD compared with non-Black patients within the first 2 years after implantation. 15 This is consistent with findings from the SCD-HeFT trial demonstrating that mortality risk was greater among Black recipients of an ICD compared with non-Black patients but without a significant difference in the rate of ICD shocks. 34 Furthermore, while long term follow-up of patients enrolled in MADIT-II trial demonstrated benefit of a primary prevention ICD, 35 this finding was not seen among the 102 enrolled Black patients.…”

“…Thus, in the contemporary literature, race mostly reflects a social construct that may or may not have any rooting in biology or physiology and is often a surrogate for a host of confounding factors such as insurance status, 9 , 13 social determinants of health, 14 and comorbidity, to name a few. 15 Importantly, most of the historical literature examining race subgroups often focuses solely on Black and White patients (rather than those who identify with other races) and categorizes race as “White” and “non-White” or “other,” significantly limiting the interpretation of findings among subgroups of Black, Asian, and Hispanic patients as well as patients who identify with other racial and ethnic subgroups.…”

Understanding Outcomes with the EMBLEM S-ICD in Primary Prevention Patients with Low EF Study (UNTOUCHED): Clinical characteristics and perioperative results

“…Similar increased comorbidity in primary prevention 35% black patients was reported in the PROSE-ICD trial. 12 Black patients had longer procedure times but less frequently underwent DFT. Further study is warranted in this population.…”

Heart Failure with Improved Ejection Fraction: Insight into the Variable Nature of Left Ventricular Systolic Function

“…Approximately 25% of patients with implanted ICD experience LVEF improvement and meet the criteria of HFimpEF. In the PROSE-ICD study [ 77 ], the incidence rate for appropriate ICD shock per 100 patient-years was 5.5, 2.4 and 1.7% for LVEF < 35%, 36–54% and LVEF > 55%, respectively. In a meta-analysis of 16 studies, patients with HFimpEF had half the risk of ICD-rendered therapy compared to the HFrEF group [ 69 ].…”