Black Adults Face CV Mortality Beyond Their Predicted Risk

Black men and women have “disproportionately high and excess” cardiovascular mortality compared with other demographic groups—even when their coronary artery calcium (CAC) scores and predicted 10-year odds of developing atherosclerotic cardiovascular disease (ASCVD) would indicate similar risk, data from the CAC Consortium suggest.

These nuances, researchers say, impede clinicians’ ability to target efforts at preventive care.

“Detection of atherosclerosis is the basis for guiding primary prevention, with CAC scanning becoming an ever important part of the risk assessment process, especially among individuals where CV risk is uncertain or when significant evidence gaps exist among key, diverse populations,” Shmuel Rosenblatt, BS (University of British Columbia School of Medicine, Vancouver, Canada), and colleagues write in their paper, published recently in JACC: Cardiovascular Imaging.

Yet the evidence across diverse racial/ethnic and sex subgroups “is sparse and often inconsistent” in the literature, they point out.

Senior author Leslee J. Shaw, PhD (Icahn School of Medicine at Mount Sinai, New York, NY), told TCTMD that their study was intended to address that gap.

What they found points to  delayed referral for CAC testing, higher ASCVD risk scores, older age, and less preventive treatment in the Black population, she said. “ And at any given amount of calcium, they were much, much higher risk” of subsequently dying from cardiovascular disease—even with a CAC score of 0. “ So that shows that the risk factors are not being ultimately cared for, and there's probably a lot of other comorbidities which are influencing outcomes,” Shaw explained.

“We always hear that saying of ‘You have a long warranty period when you have a zero calcium score’ and that it's very, very low risk,” she said, adding that while this is generally true, its important for clinicians to be cautious making that assumption when caring for patients whose risk may be driven by other factors.

For Black patients, and to a lesser degree for Hispanic male patients, those with CAC scores > 100 had “sizably higher risk” of CV death compared with other demographic groups, noted Shaw.

Conventional tools for risk stratification aren’t yet taking these subtleties into account, in part because there hasn’t been enough research, she added. “ I really believe that we have to understand how each patient population uniquely gets and acquires atherosclerosis.  Until we do that, we're not going to optimally treat patients of African or Caribbean or South American descent. . . . We have to understand people's biology.”

And at any given amount of calcium, they were much, much higher risk. Leslie J. Shaw

For their study, Rosenblatt et al analyzed data for 42,964 participants (mean age 54.7 years; 35.0% women) in the CAC Consortium with self-reported race/ethnicity: 89% white, 2.3% Black, 3.1% Hispanic, 3.8% Asian, and 1.7% American Indian/Native Alaskan/Hawaiian or unspecified. Median follow-up was 11.7 years.

CV risk factors were especially prevalent among Black women, of whom 60.9% had hypertension, 16.1% had had diabetes, 13.8% were smokers, and 39.8% were obese. Among men, those who were Black had the highest rate of hypertension, at 50.9%. Diabetes rates were high among Black and Hispanic men (18.1% each) as well as Hispanic women (18.3%).

Black individuals had higher 10-year ASCVD risk, which exceeded 7.5% for 43% of women and 57.3% of men, with the highest mortality among the various demographic groups. Among those with >7.5% ASCVD risk, Black male and female participants, as well as Hispanic females, had increased CV mortality.

People With > 7.5% ASCVD Risk: CV Mortality

Black women in particular tended to have higher CAC scores: 31.7% had a CAC score of 0-99 and 18.9% had a score > 100 (versus 25.8% and 14.5%, respectively, of White women).

For all the different subpopulations, having a CAC score > 100 strongly predicted risk of CV death (P < 0.007). Yet the impact was greater for Black and Hispanic participants compared with the other racial/ethnic groups, even when adjusting for predicted ASCVD risk.

CAC Score > 100: CV Mortality

Even in lower-risk groups, indicated by a 0 CAC or ASCVD risk score < 5%, CV mortality was increased by six- to ninefold for Black men and women compared to other participants.

Rosenblatt and colleagues tested various models that did or did not incorporate the two risk-assessment tools, finding that “although clinical risk factors and CAC explain a significant proportion of the observed variability in CV mortality, the addition of race and ethnicity provides incremental risk information, particularly for men.”

However, “as is the case for many observational studies focusing on disparities in CV outcomes, we cannot reveal the precise mechanisms, nor do we have data to unearth the contributions of racism or other social determinants of health,” the authors acknowledge.

Avoiding Delays

There are still some clear messages, they add. For one, “there is a delayed referral pattern for risk assessment leading to heightened CV mortality for Black women and men when compared to other subgroups,” they write. Additionally, the greater mortality risk seen among seemingly low-risk—at least according to ASCVD risk or CAC scores—Black individuals and Hispanic men points to “residual risk that is not fully mediated by coronary atherosclerosis.”

Better strategies for early detection and community outreach in at-risk Black and Hispanic individuals are needed to avoid delays in preventive care, according to the researchers.

Also needed, said Shaw, are tweaks to existing risk scores and screening methods that are inexpensive enough to implement at a large scale. “More comprehensive assessments would be a good next step,” she said, adding that these goals are timely given that the American College of Cardiology and American Heart Association are currently working to update their prevention guidelines.

In the meantime, clinicians treating Black patients and other groups whose risk may not be fully captured by common tools should consider things like how long the individual has been exposed to traditional risk factors like smoking or high blood pressure, whether they’ve consistently been on medical therapy to address those needs, and if their comorbid conditions have been adequately controlled.