Black Patients with ICDs Experience Higher Disease Burden than White Patients

Ilan Goldenberg, MD

Credit: LinkedIn

Black patients in the United States with nonischemic cardiomyopathy (NICM) and an implantable cardioverter-defibrillator (ICD) experienced a significantly higher burden of disease than White patients with the same device, according to new research.¹

An analysis of clinical trial data conducted over a 20-year period by the Clinical Cardiovascular Research Center (CCRC), data showed Black patients with ICDs were often significantly younger than White patients and had a higher rate of post-implant cardiac events and mortality risk.

“It is possible that Black patients are not managed as well as White patients because of health care disparities, but we did not identify any significant differences in our study,” Ilan Goldenberg, MD, principal investigator, and director of CCRC at the University of Rochester Medical Center, said in a statement.² "We did identify that after 1 year, Black patients were more likely to discontinue some medications, but the reasons for that are unknown as well. The younger age of onset and the increased rate of comorbidities, such as diabetes and hypertension, among Black patients with NICM is striking and may contribute to the worse outcomes due to more advanced heart disease.”

When a patient is at risk for cardiac arrest, an ICD helps monitor heart rhythm and will deliver an electric shock if an abnormality is detected. Black patients are known to have a greater risk of NICM when compared with White Patients. The current analysis aimed to evaluate differences in tachyarrhythmia risk among nearly 4000 ICD recipients in the US enrolled in the primary prevention ICD trials.

Outcome measures included ventricular tachyarrhythmia (VTA), atrial tachyarrhythmia (VTA), atrial tachyarrhythmia (ATA), ICD therapies, VTA burden (using Andersen-Gill recurrent event analysis), death, and predicted benefit of the ICD. For analyses, all events were adjudicated blindly. Investigators compared outcomes between self-reported Black patients versus White patients with non-ischemic and ischemic cardiomyopathy

Investigators noted Black patients were more likely to be female (35% versus 22%) and younger (mean age, 57 years vs. 62 years), with a higher frequency of comorbidities, compared with White patients. For those with NICM, Black patients experienced a higher rate of first VTA, fast VTA, ATA, and appropriate and inappropriate ICD therapy (VTA ≥170 bpm, 32% vs. 20%; VTA ≥200 bpm, 22% vs. 14%; ATA, 25% vs. 12%; appropriate therapy, 30% vs. 20%; and inappropriate therapy, 25% vs. 11%; P <.001 for all).

Additionally, the multivariable analysis suggested Black patients with NICM experienced a higher risk of all arrhythmia or ICD therapy (VTA ≥170 bmp, hazard ratio [HR], 1.71; VTA ≥200 bpm, HR, 1.58; ATA, HR, 1.87; appropriate therapy, HR, 1.62; inappropriate therapy, HR, 1.86; P ≤.01 for all). In addition, they experienced a higher burden of tachyarrhythmia or therapies (VTA, HR, 1.84; appropriate therapy, HR, 1.84; P <.001 for both) and a higher risk of death (HR, 1.92; P = .014).

On the other hand, the risk of all types of tachyarrhythmia, ICD therapy, or death was similar between Black patients and White patients with ICD. Both patient demographics were shown to derive a significant and similar benefit from ICD implantation. Investigators noted only NICM showed stark differences between Black and White patients.

Applying the Gini Index to their results, investigators looked at zip codes across the US to compare an individual’s wealth to the surrounding area. In this study, index scores suggested Black patients tended to come from areas with lower socioeconomic status. As a result, the investigative team suggests Black patients with an ICD should receive early aggressive treatment, meaning closer monitoring and referring to specialists as needed.

“We believe the main implication of this study is that because we now know that Black patients who have heart failure are more likely to have more advanced arrhythmias, they should be considered earlier for an ICD defibrillator to protect them from sudden cardiac death,” Goldenberg said.²

References

1. Younis A, Ali S, Hsich E, et al. Arrhythmia and Survival Outcomes Among Black Patients and White Patients With a Primary Prevention Defibrillator. Circulation. 2023;148(3):241-252. doi:10.1161/CIRCULATIONAHA.123.065367
2. Racial disparities discovered in patients with cardiac devices. EurekAlert! July 17, 2023. Accessed July 21, 2023. https://www.eurekalert.org/news-releases/995565.