Nav: Home

Racial disparities in sudden cardiac death rates cannot be explained by known risk factors

November 12, 2018

PHILADELPHIA--While it's well reported that black patients are twice as likely as white patients to succumb to sudden cardiac death (SCD), the underlying factors that propel this disparity remain unknown. According to a first-of-its-kind study from Penn Medicine, published online today in the Journal of the American College of Cardiology, researchers showed that even after controlling for risk factors like income, education, smoking, exercise, and bad cholesterol, among others, black patients remained at significantly higher risk for SCD.

"While greater public health efforts to identify and decrease health risks in black populations will be a critical step in reducing their higher risk of SCD, our data suggest that it may not eliminate racial disparities entirely," said lead author Rajat Deo, MD, MTR, an associate professor of Cardiovascular Medicine in the Perelman School of Medicine at the University of Pennsylvania. "Our research demonstrates other factors, perhaps genetic, are at play, and we need more exploration to better understand this disparity."

Each year in the United States, there are more than 350,000 out-of-hospital SCDs--the immediate cessation of the heart's ability to function properly. SCD occurs unexpectedly, with little to no warning signs or symptoms, and it strikes most commonly among those in the general population without a history of cardiovascular disease. Past studies have consistently shown black patients have a higher incidence of SCD compared to white patients, but this study marked the first time a rigorous, prospective population-based analysis adjusting for risk factors.

The researchers evaluated 22,507 participants over the age of 45 (9,416 black patients and 13,091 white patients) without a history of cardiovascular disease using data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a prospective, population-based cohort of adults from across the United States. Among that group, there were nearly twice as many SCD events in among black patients over an average of six years of follow-up.

To evaluate whether racial differences in SCDs were attributable to differences in the prevalence of risk factors or to an underlying susceptibility, the researchers performed analyses that adjusted for various demographics and socioeconomic factors including: lower incomes; cardiovascular risk factors such as blood pressure and diabetes; and behavioral measures of health, such as alcohol use, stress and depression. From the time participants enrolled in the study through about six years of follow up, researchers found the risk of SCD for black patients was still nearly double that of white patients, and it did not appear to be directly impacted by these known risk factors.

"At the end of the day, we just don't have a full understanding of why patients who are black are more likely to succumb to SCD - a clear problem and knowledge gap on many levels," Deo said. "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 authors suggest that the pathology underlying SCD may differ in each of these groups and could be a contributor to the disparity, the authors noted. For instance, autopsy studies have revealed that coronary artery disease accounts for a lower percentage of SCDs in black patients, despite their known higher burden of hypertension, diabetes, and chronic kidney disease. Other cardiac issues, such as cardiac hypertrophy--the thickening of the heart muscle--are also more commonly found in autopsies of black patients, whereas autopsies of deceased white patients are more likely to show coronary plaque rupture.

"Future research is needed to understand the mechanisms underlying these racial differences," the authors wrote. In the interim, Deo emphasizes that "the current findings underscore the critical importance of community-based interventions to increase awareness about SCD, warning symptoms, and improve resuscitation rates from cardiac arrest."
The study was supported by a cooperative agreement from the National Institute of Neurological Disorders and Stroke, National Institutes of Health, Department of Health and Human Services (U01-NS041588). Additional support was provided by grants from the National Heart, Lung, and Blood Institute (R01-HL080477 and K24-HL111154). It was also supported, in part, by the Winkelman Family Fund in Cardiovascular Innovation.

Penn Medicine is one of the world's leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System, which together form a $7.8 billion enterprise.

The Perelman School of Medicine has been ranked among the top medical schools in the United States for more than 20 years, according to U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $405 million awarded in the 2017 fiscal year.

The University of Pennsylvania Health System's patient care facilities include: The Hospital of the University of Pennsylvania and Penn Presbyterian Medical Center -- which are recognized as one of the nation's top "Honor Roll" hospitals by U.S. News & World Report -- Chester County Hospital; Lancaster General Health; Penn Medicine Princeton Health; Penn Wissahickon Hospice; and Pennsylvania Hospital -- the nation's first hospital, founded in 1751. Additional affiliated inpatient care facilities and services throughout the Philadelphia region include Good Shepherd Penn Partners, a partnership between Good Shepherd Rehabilitation Network and Penn Medicine, and Princeton House Behavioral Health, a leading provider of highly skilled and compassionate behavioral healthcare.

Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2017, Penn Medicine provided more than $500 million to benefit our community.

University of Pennsylvania School of Medicine

Related Cardiovascular Disease Articles:

A talk with your GP may prevent cardiovascular disease
Having a general practitioner (GP) who is trained in motivational interviewing may reduce your risk of getting cardiovascular disease.
Dilemma of COVID-19, aging and cardiovascular disease
Whether individuals should continue to take angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in the context of coronavirus disease 2019 (COVID-19) is discussed in this article.
Air pollution linked to dementia and cardiovascular disease
People continuously exposed to air pollution are at increased risk of dementia, especially if they also suffer from cardiovascular diseases, according to a study at Karolinska Institutet in Sweden published in the journal JAMA Neurology.
New insights into the effect of aging on cardiovascular disease
Aging adults are more likely to have - and die from - cardiovascular disease than their younger counterparts.
Premature death from cardiovascular disease
National data were used to examine changes from 2000 to 2015 in premature death (ages 25 to 64) from cardiovascular disease in the United States.
Ultrasound: The potential power for cardiovascular disease therapy
In the current issue of Cardiovascular Innovations and Applications volume 4, issue 2, pp.
Despite the ACA, millions of Americans with cardiovascular disease still can't get care
Cardiovascular disease (CVD) is the leading cause of death for Americans, yet millions with CVD or cardiovascular risk factors (CVRF) still can't access the care they need, even years after the implementation of the Affordable Care Act (ACA).
Excess weight and body fat cause cardiovascular disease
In the first Mendelian randomization study to look at this, researchers have found evidence that excess weight and body fat cause a range of heart and blood vessel diseases (rather than just being associated with it).
Enzyme may indicate predisposition to cardiovascular disease
Study suggests that people with low levels of PDIA1 in blood plasma may be at high risk of thrombosis; this group also investigated PDIA1's specific interactions in cancer.
Cardiovascular disease in China
This study analyzed data from the Global Burden of Disease Study to look at the rate of cardiovascular disease (CVD) in China along with death and disability from CVD from 1990 to 2016.
More Cardiovascular Disease News and Cardiovascular Disease Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Clint Smith
The killing of George Floyd by a police officer has sparked massive protests nationwide. This hour, writer and scholar Clint Smith reflects on this moment, through conversation, letters, and poetry.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at