Blacks are twice as likely as whites to experience sudden cardiac arrest

Blacks have more than double the risk as whites to experience sudden cardiac arrest (SCA), and at a much earlier age, according to research published in the journal Circulation.

Researchers also found that blacks had higher rates than whites of well-established risk factors for cardiovascular disease, including diabetes (52% vs 33%), high blood pressure (77% vs 65%), and chronic kidney failure (34% vs 19%).

“Cardiac arrest is recognized by the ‘bad company’ it keeps. So the mantra has been: prevent coronary artery disease, prevent sudden cardiac death,” said lead investigator Sumeet S. Chugh, MD, associate director of the Cedars-Sinai Heart Institute in Los Angeles, CA. “As health care professionals, we should be aware of a broader spectrum of risk factors for our black patients. If we only focus on reducing coronary artery disease, we are unlikely to offer them the same benefit we offer white patients.”

Sudden cardiac arrest is a major cause of death in the United States, contributing to 300,000 to 350,000 deaths each year and accounting for about 50% of all cardiovascular deaths. But research on SCA lacks specific information about non-white populations.

For this study, researchers collected data on 1,745 white and 179 black residents in the Portland, OR, metropolitan area who experienced sudden cardiac arrest between 2002 and 2012.

Incidence of SCA among black men was 175 per 100,000 people, compared  with 84 per 100,000 for white men. For black women, the incidence was 90 per 100,000, compared with 40 per 100,000 for white women.

The researchers also found that blacks, on average, were more than 6 years younger than whites at the time of SCA. The majority of blacks were younger than 65 when SCA occurred; the majority of whites were older than 65. 

"We do not know why African-Americans are more likely to have sudden cardiac arrest," said lead author Kyndaron Reinier, PhD, research scientist in the Arrhythmia Research Laboratory at the Cedars-Sinai Heart Institute. "It could be due to the higher burden of illnesses that increase risk of heart disease, like hypertension and diabetes. Or it could be genetic because we know that certain health conditions are more prevalent in particular groups of people. Or, the reason could be environmental, such as access to good health care. But there is no doubt that there are differences between the races when it comes to clinical outcomes."

Results also showed that blacks who experienced SCA had the same rates as whites of coronary artery disease, long considered the strongest predictor of risk. However, blacks had a higher prevalence of non-coronary cardiac risk factors for SCA: congestive heart failure (43% vs 34%), left ventricular hypertrophy (77% vs 58%), and a longer QT interval (466 ± 36 vs 453 ± 41). This finding suggests that use of a broader spectrum of SCA risk factors—including left ventricular hypertrophy and specific ECG parameters—may provide new opportunities to lower the significant SCA burden in blacks compared to other racial groups, the authors wrote. In addition, 52% of blacks in the study had diabetes compared with 33% of whites.

“In black patients, we found our study reinforces the importance of a healthy lifestyle to avoid developing certain sudden cardiac arrest risk factors, including high blood pressure, diabetes, and chronic kidney disease,” Dr. Chugh said.

Researchers believe the study results should be replicated in other communities and recently expanded their study to California’s Ventura County, which has a large Latino population.