Race May Be a Proxy for Many Disparities in CVD Treatment, Outcomes

Not only do black patients have different baseline characteristics compared with white patients related especially to socioeconomic status and social factors, but also these characteristics are associated with a threefold higher 5-year mortality rate following acute MI, according to new research.

“We all know there's a long history of racial disparities in terms of outcomes post-MI and a number of cardiovascular diseases. What we were trying to look at here was whether race served as a marker for these outcomes, or whether these outcomes were actually driven by race itself,” lead author Garth Graham, MD, MPH (Saint Luke’s Mid America Heart Institute, Kansas City, MO), told TCTMD. “What was surprising was the degree to which mortality was impacted by these outcomes.”

The cohort study, published online last week ahead in JAMA Network Open, included 6,402 patients from the PREMIER and TRIUMPH registries who were recovering from an acute MI at one of 31 US hospitals between 2003 and 2008. Mean patient age was 60 years, and 25.7% self-identified as black.

The researchers combined all patient characteristics to calculate a propensity score that could discriminate race—this analysis showed that socioeconomic status, followed by social factors and medical history, stood out as the biggest differences between self-described white and black patients.

Using race alone, 5-year mortality was higher for black patients than for white patients (28.9% vs 18.0%; HR 1.72; 95% CI 1.54-1.92).

When the propensity score was used—regardless of actual patient race—individuals who fell in the lowest and highest quintiles of the score associated with being black had 5-year mortality rates of 15.5% and 31.0%, respectively (P < 0.001). After adjusting for propensity score, there was no significant difference in mortality risk between black patients and white patients (adjusted HR 1.09; 95% CI 0.93-1.26).

“Although not definitive, these findings indicate that, even without controlling for genetic factors, the mortality risk after acute MI is not different between black patient and white patients after adjusting for socioeconomic, psychosocial, and health status characteristics,” the authors conclude. “Our finding that socioeconomic status–related variables were the strongest differentiator between black patients with acute AMI and white patients with AMI suggests that further understanding of the mechanism by which socioeconomic status affects survival may be an important target for future research.”

Graham hopes this study will help physicians appreciate the extent to which race is merely a proxy for other, more important factors to consider. “Certainly, there are these characteristics that are more prevalent in one racial group versus another, but it's actually [something] independent of the race of those individuals that appeared to be significantly driving health outcomes at least 5 years post-MI.” Additionally, characteristics like zip code, educational status, insurance, and monthly financial reserves and dynamics cannot be controlled in the hospital, he said. “Clearly those things have a significant impact on outcomes posthospitalization.”

Doctors “should be aware of those factors and the degree to which those factors can impact outcomes,” Graham continued. “As we look not just at the physician level but even at the health system and the broader national level, understanding how those factors impact outcomes should drive how we expect to try to improve those outcomes and how we manage those outcomes.”

Next, his research team is planning “to piece apart the more granular impact of that socioeconomic status including things like location, education, and economic status, and how those impact outcomes,” Graham said.

‘The Company You Keep’

Commenting to TCTMD, Jacob A. Udell, MD, MPH (University of Toronto, Canada), who recently conducted a similar analysis using the National Cardiovascular Data Registry, said this study was a “very novel” way to assess how different societal factors affect cardiovascular outcomes.

“It was really fascinating to see that once you consider everything in its totality, ‘the company that you keep’ . . . seems to be really driving the disparities that we see between races and treatment and outcomes more so than the color of your skin,” he said. “That really [is] a very important observation with regards to disproving and putting [to] rest that there's something biologically different that might be driving the differences in outcomes, and [instead suggests] that there is likely either a process measure or an environmental factor—in this case potentially where you live and how much money you make and how much resources you have access to, and how much deprivation or lack thereof you have, stress, et cetera—that could be driving differences in how people do.”

This paper is prescient particularly given the midterm election results just tallied in the United States, Udell noted, given the controversial ideas that exist about healthcare now. Research like this is starting to highlight that differences in treatment and outcomes are “beyond biology and that really we can control our destinies if we decide to change the way that resources are distributed,” he said. Further, this study underscores the importance of decision-making “that will benefit I think society as a whole, and not just one particular group.”

In order to play their part in reducing the disparity, Udell said that physicians should embrace standardization of care, recognizing that circumstances may dictate variations. “If we’re all offering the same access, the same response rate, the same cocktail and menu of therapies that are recommended according to best practices and access to either the lifesaving generic medicines versus expensive resuscitation and coronary revascularization therapies, that will help minimize the differences in socioeconomic background,” he suggested.

Going forward, Udell would like to see randomized studies looking at what is “’best practice’ in the areas that we consider ‘rich’ socioeconomic background and see if we can actually modify the destiny of people in rural or low socioeconomic backgrounds by modifying access to care.” Examples could be optimizing a pathway to early revascularization or ensuring universal access to medications, he said. “But maybe the key is to focus particularly on the high-risk, low-access, high-deprivation portions of our communities first to see whether or not they are the most sensitive to change since they seem to have the biggest disparities.”