Health Disparities Across the Continuum of ASCVD Risk

Abstract

Purpose of the Review:

Despite marked progress in cardiovascular disease management in the last several decades, there remain significant, persistent disparities in cardiovascular health in historically marginalized racial and ethnic groups. Here, we outline current state of health disparities in cardiovascular disease, discuss the interplay between social determinants of health, structural racism, and cardiovascular outcomes, and highlight strategies to address these issues.

Recent findings:

Across the continuum of atherosclerotic cardiovascular disease (ASCVD) prevention, there remain significant disparities in outcomes including morbidity and mortality by race, ethnicity, and socioeconomic status (SES). These disparities begin early in childhood (primordial prevention) and continue with a higher prevalence of cardiovascular risk factors (primary prevention), and in the uptake of evidence-based therapies (secondary prevention). These disparities are driven by social determinants of health and structural racism that disproportionately disadvantage historically marginalized populations.

Summary:

Structural racism and social determinants of health contribute to significant disparities in cardiovascular morbidity and mortality.

Introduction

Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of mortality in the United States (US) [1]. While overall ASCVD mortality has declined in recent decades, there remain marked, persistent disparities in ASCVD outcomes among diverse populations, including by sex race/ethnicity, socioeconomic status (SES), and insurance status. Structural racism and social determinants of health (SDOH) are crucial drivers of these disparities. Here, we focus on the current state of ASCVD disparities by race/ethnicity, SES, and the intersection of SDOH on ASCVD risk, treatment, and outcomes. We explore disparities across the continuum of ASCVD risk and disease, namely across primordial, primary, and secondary CVD prevention and treatment of ASCVD. We contextualize these disparities with the interplay between structural racism, SDOH, and cardiovascular health, and outline potential individual and population-level strategies to address these inequities.

Structural Racism and Social Determinants of Health

Structural racism refers to the legitimization of interpersonal, societal, and institutional dynamics that routinely disadvantage minoritized racial/ethnic groups and lead to adverse health outcomes [2]. Structural racism creates disparities through inequitable distribution of resources, lack of access to affordable healthcare, and systemic biases that lead to poorer healthcare outcomes.

The WHO defines SDOH as “the circumstances in which people are born, grow, live, work, and age, and the systems put in place to deal with illness” [3]. However, it has been repeatedly demonstrated that racial and ethnic disparities persist even after accounting for individual risk factors [2, 4]. At every education level, Black and Hispanic people have a lower income, purchasing power, and worse health outcomes [5]. After controlling for cardiovascular risk factors, Black patients still have a higher mortality from ASCVD than NHW patients [4]. Structural racism is a key contributor to SDOH-driven disparities. Although SDOH are now increasingly recognized as the root cause of ASCVD risk factors and disparities, awareness remains limited [2]. In a study of 344 US cardiologists, 34% agreed that there are significant disparities in the US healthcare system based on racial and ethnic differences, but only 5% believed that disparities existed within their own practices. Many attributed existing disparities individual patient factors rather than systemic differences [6].

Cardiovascular disease accounts for at least one-third of the disparities in mortality between Black and Non-Hispanic White (NHW) patients [7]. Black Americans continue to experience 30% higher mortality from ASCVD and 45% higher mortality from stroke compared with NHW patients [1]. Racial and ethnic disparities may account for approximately $230 billion in healthcare costs, with over 59% of those excess expenditures attributed to health disparities in Black Americans and 36% to disparities in Hispanic populations [8]. These disparities start early childhood, persist into adulthood with the development of cardiovascular risk factors and disease, and persist through treatment variation in the management of acute and chronic ASCVD [Figure 1].

Figure 1.

Continuum of Disparities in Diverse Racial/Ethnic Groups and Low SES Patients

Disparities in Primordial Prevention of Cardiovascular Disease

Primordial prevention aims to mitigate cardiovascular risk through early life efforts to prevent the development of ASCVD risk factors. There is a growing body of research advocating for early childhood interventions for primordial prevention [9], especially given that the development of adverse risk factors in adolescence accelerates atherosclerotic disease, with its subclinical effects preceding the development of clinical ASCVD by 20–30 years [10, 11].

ASCVD risk can begin as early as in utero as the fetus is exposed to maternal risk factors, including preeclampsia and gestational diabetes. However, there are significant disparities in maternal morbidity and mortality among difference races and SES groups, leading to a cascading effect of increased cardiovascular risk in their offspring. Black and Hispanic patients have a 2.1 and 1.3 times higher risk of severe maternal morbidity as compared to NHW mothers (p<0.05) [12]. A study analyzing peripartum maternal morbidity and mortality found that while hospital rates of maternal morbidity varied widely across a given city, Black mothers were more likely to deliver at higher morbidity, lower performing hospitals than NHW mothers [13]. In utero exposures can then lead to a lifelong elevated risk of cardiovascular disease. Babies born to mothers with preeclampsia have a statistically significantly higher risk of cardiovascular disease as adults, with severe maternal preeclampsia being an independent risk factor for cardiovascular disease [14]. Adults who were exposed to gestational diabetes in utero are more likely to have high blood pressure, obesity, and hyperglycemia [15].

Exposure to cardiovascular risk factors begins in utero and continues into childhood and adolescence. Cardiovascular health is significantly impacted by the built environment, or the environment in which people live and work, including access to safe venues for exercise, healthy dietary options, and affordable healthcare. Multiple studies have now demonstrated that access to active transportation, parks, and recreation facilities lead to lower prevalence of risk factors for CVD and CVD itself [16, 17, 18, 19]. However, low SES and racially diverse neighborhoods are less likely to have access to all of these facilities [20]. Black and Hispanic individuals live in neighborhoods that are typically of lower SES, and are less likely to have access to exercise venues or affordable healthy meals [16, 2]. Although access to parks and community centers has a positive cardiovascular health impact, low SES communities are less likely to have access to affordable, well-kept amenities that allow for safe physical activity [22]. The built environment has adverse cardiovascular effects which are concentrated in low SES communities [19]. Such institutionalized disadvantages can contribute significantly to elevated early-life cardiovascular and cardiometabolic risks including obesity, hypertension (HTN), and diabetes mellitus (DM) [23].

Disparities in Primary and Secondary Prevention of ASCVD

Recognizing Disparities in Modifiable Risk Factors

In the presence of established ASCVD risk factors, the risk of cardiovascular disease remains elevated despite optimal risk factor management efforts [24, 8]. There are five major modifiable risk factors for cardiovascular disease that primary and secondary prevention focus on – hypertension, hyperlipidemia, diabetes, obesity, and smoking [25]. Black and Hispanic patients have a higher prevalence of these risk factors, especially HTN and DM in Black patients and DM and hypertriglyceridemia in Hispanic patients. Many of these risk factors begin early in childhood and are related to disparities in the built environment. Black and Hispanic children and adolescents may have a higher baseline blood pressure and a higher prevalence of diagnosed HTN [26], a significantly higher proportion of obesity [27] and significantly higher glycosylated hemoglobin levels [28] compared with NHW children and adolescents. In a study of 184 children, Black children had higher average body mass index (BMI; average percentile of 95% vs 87%), higher prevalence of left ventricular hypertrophy (56% vs 26%), and higher plasma renin levels (8.7 vs 3.6 ng/mL) as compared with non-Black children [29]. Another study demonstrated a steady relationship between socioeconomic status and obesity; with an incremental decrease in SES, there was a proportional incremental increase in rates of obesity [30]. Development of risk factors earlier in life portends a worse outcome by adulthood [11]. However, this risk can be mitigated by early intervention, underscoring the need to systematically address early life health disparities [31].

Disparities in Risk Mitigation

Once risk factors have been identified, the focus shifts to appropriate management and modification of these risk factors. However, even after recognition of risk factors, there are significant disparities in modification and mitigation of risk factors. Black populations experience a higher burden of HTN, especially uncontrolled HTN, as compared with NHW populations. While Black patients were more likely to be aware of their diagnosis of HTN and more likely to be on treatment than NHW patients, they remained less likely to achieve targets for BP goals (OR 0.73, 95% CI 0.64 to 0.83) in a study of 11,701 patients [32]. Both Black and Hispanic patients have an elevated lifetime risk of DM but lower glycemic control than their NHW counterparts [33]. Hispanic Americans may experience higher rates of obesity, HTN, and hypertriglyceridemia than NHW patients [34, 35]. Black women experience the highest burden of risk, with a 69% higher mortality rate from coronary artery disease as compared with NHW women [36]. Black women are also two and a half times as likely to die from heart failure as compared with NHW women [37]. Disparities in peripartum complications and adverse pregnancy outcomes, including pre-eclampsia and peripartum cardiomyopathy, may contribute to this disproportionately higher burden of cardiovascular risk [39]. Peripartum morbidity and mortality may be higher in Black women as compared with other groups [39, 40]. Black women who develop preeclampsia during their pregnancies have significantly higher mortality rates despite similar prevalence [40]. In a cohort of 101,741 peripartum patients, Black woman had the highest rates of morbidity and all-cause mortality, including new onset heart failure (p<0.01) [41].

Similar cardiometabolic disparities are seen by SES. Patients of low SES status are more likely to present with more untreated risk factors, including a higher prevalence of HTN [42], DM, and cigarette use [43]. Patients of lower SES are also less likely to achieve on-treatment targets for risk factor control, including smoking cessation, lipid control, and BP control [44]. At time of diagnosis, patients of lower SES are more likely to present with more severe cardiac disease than those of higher SES [45]. A systematic review of disparities by SES from initial diagnosis and primary prevention of ASCVD to treatment and long-term outcomes found that the inequities were greatest in the early disease stages, indicating potential underdiagnosis and primary prevention disparities [31]. Attempts to ameliorate these disparities must therefore incorporate a focus on addressing key SDOH barriers including timely access to preventive healthcare.

Medication Prescription and Adherence

There remain stark differences in guideline-directed cardiovascular medication prescription and adherence rates by race/ethnicity and SES. Black, Hispanic (versus NHW) and low SES (versus higher SES) patients are less likely to be prescribed evidence-based therapies for coronary artery disease and acute coronary syndrome (ACS), and experience lower medication adherence and persistence rates [46, 47, 48].

Statin prescription rates are 30% lower in Black and Hispanic patients than in NHW patients [49]. Black and Hispanic patients have significantly lower statin adherence rates than their NHW counterparts, which in turn is independently associated with increased all-cause mortality [47]. While aspirin and beta blocker prescription rates are lower among certain racial/ethnic groups, these discrepancies are attenuated when adjusting for risk factors [48]. Patients of lower SES status are less likely to be prescribed statins and beta blockers after ACS events [46]. On the other hand, multiple studies suggest that prescription rates for angiotensin converting enzyme-inhibitors (ACE-Is) and angiotensin receptor blockers (ARBs) are higher among low SES groups [50, 51].

One year after discharge, Black and Hispanic women were the least likely to be adherent to evidence-based therapies, followed by Black and Hispanic males, with NHW males having the highest rates of adherence by race/ethnicity and sex [52]. These differences persisted after accounting for insurance coverage [53]. Similar disparities exist in socioeconomic status and education levels. Patients of lower SES were less likely to be adherent to medications in the first year following discharge after an ACS event compared with patients of higher SES [44].

Reasons for decreased medication persistence may be multifactorial and may include provider practice variation, lack of provider-patient trust, affordability, and side effects. Surveys have indicated that Black patients are less likely than NHW patients to trust providers and more likely to be concerned about adverse effects of recommended medications and experimentation by hospitals, which relates to the history of deeply unethical medical practices in minoritized populations [54]. A qualitative study utilizing focus groups to explore barriers to research participation in Black populations found that hesitation stemmed from concerns about experimentation and ongoing discriminatory practices independent of the individual’s specific experience with healthcare [55]. Moreover, qualitative studies of physicians’ beliefs demonstrate concerning biases and practice variation based on race/ethnicity and SES. In a study of 613 encounters evaluated by 193 providers, NHW patients were more often rated as likely to adhere to treatment (57% vs 42% in all Non-White patients, p<0.001), intelligent (26% vs 13%, p<0.0001), and rational (37% vs 20%, p<0.05), as compared with Black, Hispanic, and other racial groups [56]. Another study found that patients’ SES may affect prescription rates as providers struggle to balance cost and adherence, leading to lower rates of evidence-based medication prescription [57].

Potential strategies to achieve equitable medication utilization, or pharmacoequity, include improved patient-provider trust, optimizing and equalizing guideline-directed prescription rates, and minimizing clinical inertia and practice variation by race/ethnicity and SES [58]. Pharmacoequity can be established by improving the access to, cost of, and quality of therapeutic care [58]. Multiple studies have found that greater insurance coverage and lower out-of-pocket payments significantly increase adherence rates [59, 36]. Patients with better insurance coverage have decreased rates of major adverse cardiac events (MACE) and revascularization events [59]. Overcoming medication prescription and adherence inequities needs to be a critical goal for efforts addressing cardiovascular health inequities.

Initial Presentation of ACS

Black and Hispanic patients are less likely to undergo a cardiac evaluation after presenting with chest pain compared with NHW patients [60, 61]. They are less likely to be triaged as a higher level of acuity, less likely to undergo electrocardiogram (ECG) and cardiac enzyme testing, and less likely to have cardiac monitoring ordered, as compared with their NHW counterparts [60, 62]. In a study of 4368 patients who underwent a cardiac workup after presenting with chest pain, NHW patients received an ECG significantly faster than non-White patients (24 minutes vs 39 minutes, p=0.01) [63]. These differences are also observed by SES. Medicaid patients or uninsured patients are less likely to be triaged to a higher acuity and less likely to undergo ECG and cardiac enzyme testing [60, 62]. Disparities in ACS recognition and early stratification may delay crucial evidence-based treatments including medical therapies and revascularization.

Revascularization

Rates of revascularization after acute myocardial infarction (AMI) are significantly lower in certain racial/ethnic groups and low SES populations. Studies have demonstrated that revascularization is similarly effective across all races [64]; despite this, Black and Hispanic patients have significantly lower rates of revascularization than NHW patients [65] even after accounting for insurance status [66]. Patients of lower SES are also less likely to undergo revascularization for ST-elevation myocardial infarctions (MI) than patients of higher SES [67]. Reasons for lower revascularization rates are multifactorial, including limited access to resource rich facilities, decreased referral rates, and systemic bias.

Physician attitudes towards the efficacy of revascularization therapy among diverse groups may contribute to decreased referral rates. When presented with multiple case studies, physicians were significantly less likely to refer female and Black patients compared with NHW male patients [68]. A survey attempting to understand the effect of race and SES on provider practice found that nonwhite patients were more likely to be associated with assumptions of poor adherence and follow up, lower SES status, and decreased feelings of “personal affiliation” with the patient [56].

Revascularization rates in Black and Hispanic populations may also be affected by differential resources in hospitals that treat low SES and diverse racial/ethnic groups. Facilities in primarily Black and Hispanic communities are less likely to have access to newer medical therapies, cardiac catheterization, or CABG capabilities [20, 69]. Patients may require transfer to reperfusion centers in the absence of revascularization abilities. However, an analysis of transfers to cardiac catheterization-equipped facilities for AMI found that time to transfer was significantly higher for Black and Hispanic patients than for NHW patients [70, 71]. In patients presenting with AMI to cardiac catheterization-equipped centers, the average door-to-balloon time (DTB) time is significantly higher in Black and Hispanic patients compared to NHW patients, which persisted despite accounting for hospital variation in DTB times [70]. DTB times are higher in patients of lower SES than in patients of higher SES [67].

Coronary Artery Bypass Grafting

Black and Hispanic patients experience lower rates of indicated coronary artery bypass grafting (CABG) compared with NHW patients. In a study of 1,991 patients presenting with chest pain, eligible Black patients were less likely to be referred to CABG than NHW patients (OR 0.24, 95% CI 0.08 to 0.71) [72]. In New York, a quality improvement initiative focused on CABG outcomes provided hospitals with a report card based on postoperative mortality rates. One study suggested that an unintentional consequence of this initiative was a significant drop in CABG among patients considered high risk, who were more often Black or Hispanic [73]. Studies have demonstrated that providers believe members of low SES and diverse racial/ethnic groups are less likely to comply with treatment, and therefore to have worse outcomes [56]. This issue may be compounded by the fact that risk scores have been validated in largely NHW populations and may be less accurate predicting perioperative mortality in diverse groups - during preoperative evaluations for coronary artery bypass grafting, predicted operative mortality rates were significantly higher for certain racial/ethnic groups, yet observed mortality was no different [74].

Disparities in ASCVD Outcomes

Disparities in the diagnosis and management of disease states across the natural history of ASCVD may translate to certain differential outcomes by race/ethnicity and SES. Recurrent hospitalizations for AMI have declined significantly faster in NHW patients than in Black patients [75]. Black patients have significantly higher mortality rates from ASCVD than their NHW counterparts [78]. One study found that there was a 10% difference in 5-year mortality rates after AMI between Black and white patients (29% vs 18%) [76].

Of note, Hispanic patients have similar outcomes to NHW patients despite clear differences in treatments as above. Among both patients who were and were not revascularized after ACS events, Hispanic patients were more likely to survive to discharge than NHW patients [65]. However, Hispanic patients who present with ACS tend to be younger with no preexisting ASCVD. A study of patients with known ASCVD found that Hispanic patients had higher MACE and mortality rates within 1 year [77].

Patients of low SES experience an approximately 2-year overall reduction in life expectancy, with significant contributions from risk factors including obesity, HTN, cigarette smoking, and physical inactivity [78]. Following an ACS event, all-cause mortality is significantly higher in lower income groups than higher income groups [45]. Another study analyzing patients presenting with ACS found a significantly higher 30-day risk of death or recurrent ACS in low SES populations, with a similar risk from 30 days to 1 year [79]. SES independently correlates with recurrent ACS regardless of appropriate secondary prevention measures [80].

Tackling Structural Racism

One of the 6 overarching goals outlined by Healthy People 2030 is to “eliminate health disparities, achieve health equity, and attain health literacy to improve the health and well-being of all” [81]. A multifaceted approach is needed to dismantle structural racism and address SDOH in ASCVD [2].

Institutionalized racism must be addressed from birth onwards. Early onset of adverse cardiovascular risk factors including HTN, DM, and obesity impact the higher prevalence and earlier onset of ASCVD seen in Black and Hispanic populations [24, 8]. Efforts to tackle disparities in cardiovascular health must also include improving health literacy in adolescence, access to healthy and affordable food, and access to affordable healthcare from birth to adulthood. The effects of structural racism and SDOH must be studied rigorously at individual, community, and population levels. Community partnerships are crucial for these efforts.

Increasing representation in clinical trials and accounting for SDOH in the development of risk scores may be important as well. Existing trials in treatment and prevention of ASCVD are composed of primarily homogenous NHW male populations, limiting external generalizability [82, 83, 84]. Increasing diversity and representation in clinical trials is a first step to understanding systemic barriers to adequate representation and promoting efforts to equitably improve treatment approaches.

Finally, increased diversity and cultural competence in the medical workforce is a crucial aspect of addressing health inequities [85].

Conclusion

There remain significant disparities in ASCVD diagnosis, management, and outcomes by race/ethnicity and SES. Disparities are prominent across the continuum of ASCVD disease states across the lifespan, ranging from primordial prevention to primary and secondary prevention of ischemic heart disease and heart failure. Structural racism and SDOH are crucial, persistent drivers of such disparities. Dedicated policy, public health, community partnership, and research efforts are needed to systematically dismantle barriers and address these disparities to equitably improve ASCVD health in the US.