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Sudden cardiac death risk factors confer unexplained racial disparities
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The disparity in sudden cardiac death rates between black and white patients remains unexplained even when controlling for risk factors, including sociodemographics, comorbidity and behavioral health data, according to findings published in the Journal of the American College of Cardiology.
Researchers assessed whether racial differences in incidence of sudden cardiac death were attributed to the commonality of risk factors or underlying susceptibility to fatal arrhythmias.
“Our study is one of the first to systematically compare the risk of [sudden cardiac death] in blacks and whites across the general population after accounting for sociodemographic, behavioral and cardiovascular risk factors,” Rajat Deo, MD, MTR, associate professor of cardiovascular medicine at the Perelman School of Medicine at the University of Pennsylvania, and colleagues wrote.
The study consisted of 22,507 participants (n = 9,416 black adults; 58% women) aged at least 45 years with oversampling in the southeastern United States, representing a region with higher stroke and mortality rates than the rest of the country. The researchers used data from the REGARDS study, a population-based cohort of adults across the United States.
Participants without a history of clinical CVD were selected, with health behaviors such as smoking, physical activity, alcohol use and psychosocial factors, including depressive symptoms and perceived stress, assessed in a baseline interview.
The study’s outcomes were determined through regular 6-month telephone contact with the participants, with all out-of-hospital CV deaths undergoing further evaluation as a possible sudden cardiac death event.
Sudden death rates differ
Researchers identified 388 confirmed sudden cardiac deaths during a median follow-up of 6.1 years in the REGARDS study, but only 174 sudden cardiac deaths (n = 107 black adults) were analyzed due to the patients lacking CVD history. The age-adjusted sudden cardiac death rate per 1,000 person-years was higher in black adults (1.8; 95% CI, 1.4-2.2) compared with white adults (0.7; 95% CI, 0.6-0.9). When researchers adjusted for sociodemographics, comorbidities, behavioral measures of health, intervening CV events and competing risks for non-sudden cardiac death mortality, the risk for sudden cardiac death among black participants remained significantly high compared with white participants (HR = 1.97; 95% CI, 1.39-2.77).
Additional research is needed to understand the mechanisms underlying the racial differences in sudden cardiac death incidences, the researchers wrote.
“In the interim, the current findings underscore the importance of community-based interventions to increase awareness about [sudden cardiac death], warning symptoms and improvements resuscitation rates from cardiac arrest,” Deo and colleagues wrote.
More research needed
A deeper look at ancestry among the black population is needed to define the specific contribution, they wrote.
In a related editorial, Sumeet S. Chugh, MD, and Kyndaron Reinier, PhD, MPH, both from Cedars-Sinai Smidt Heart Institute in Los Angeles, wrote: “Incidence rates of [sudden cardiac death] among blacks are twice as high as in whites, a finding that has remained consistent over time, despite changes in heart disease prevalence and management, study designs and definitions of [sudden cardiac death]. It is possible that future research will reveal African ancestry-related gene variants that will enhance the precision of [sudden cardiac death] risk stratification.” – by Earl Holland
Disclosures: The authors and editorial writers report no relevant financial disclosures.
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