November 13, 2018
Black patients have a higher risk of sudden cardiac death (SCD) compared to white patients, according to researchers at Penn Medicine in a study just published in the Journal of the American College of Cardiology.
The study controlled for risk factors like income, education, smoking, exercise, bad cholesterol and other factors, but the data showed black patients still are significantly more at risk for SCD in comparison.
According to this study, more than 350,000 out-of-hospital SCDs occur in the U.S. every year. SCDs happen very quickly and without warning when the heart is not able to function properly, causing death to occur within minutes, according to the Cleveland Clinic.
It's also worth noting that people without histories of cardiovascular disease overwhelmingly are more frequently affected.
Previous studies have determined that blacks have a higher incidence of SCD compared to whites, but Penn’s study marked the first “rigorous, prospective population-based analysis adjusting for risk factors,” per Penn Medicine's release.
Penn researchers evaluated 22,507 participants over age of 45 without histories of cardiovascular disease using data from the Reasons for Geographic and Racial Differences in Stroke study, a collection of data of adults from across the United States.
Of that group, 9,416 of the patients were black, and 13,091 were white. The data of this group showed that there were nearly twice as many SCD events in black patients over an average of six years of follow-up.
With this information in mind, researchers wanted to determine whether racial differences in SCD cases were the result of differences in the prevalence of risk factors or to an underlying susceptibility.
To figure that out, researchers adjusted for various demographic and socioeconomic factors including: lower incomes, cardiovascular risk factors such as blood pressure and diabetes, and behavioral measures of health, including alcohol use, stress and depression.
Based off of these adjustments, researchers found the SCD risk among blacks was still nearly double that of whites, and it did not appear to be directly impacted by these risk factors.
While researchers are not entirely sure why black patients are more likely to die from SCD, they have a theory for the disparity: SCD behaves differently in each group.
Autopsy studies have shown that coronary artery disease accounts for a lower percentage of SCDs among black patients, despite their higher risk for hypertension, diabetes, and chronic kidney disease.
Other heart-related health issues, such as cardiac hypertrophy — the thickening of the heart muscle — are also more commonly found in autopsies of black patients, but autopsies of most white patients show coronary plaque rupture.
The lead author Dr. Rajat Deo, an associate professor of Cardiovascular Medicine in the Perelman School of Medicine at the University of Pennsylvania, offered this explanation:
“For many in the black community, their first clinical presentation of any cardiovascular issue is a sudden cardiac death event. Of course, we don’t know whether they have ignored symptoms such as chest pain and opted not to seek medical attention, or if this truly is the first indication of cardiovascular disease, perhaps due to a genetic predisposition. Either way, the data are staggering, and represent a pervasive problem in the black community."
The researchers believe that these findings stress the importance of community-based interventions to increase awareness about SCD.