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Racial and ethnic differences in cardiovascular risk factors and CVD have been well described in the United States for decades. For example, using national survey data on risk factor prevalence and indexes of morbidity, mortality, and overall quality of life in adults 18 years of age or older, Mensah et al22 assessed the magnitude of disparities in CVD in the United States in 2005. That assessment concluded that disparities in CVD were pervasive. In particular, racial and ethnic disparities were common in all risk factors examined. For example, hypertension prevalence was highest among blacks (48.7%) regardless of sex or educational status. Hypercholesterolemia was highest among white and Mexican-American men (49.2%) and white women (56.9%) regardless of educational status. In men, the highest prevalence of obesity was found in Mexican Americans (29.2%) who had completed a high school education.22 Black women (47.7%) with or without a high school education had a high prevalence of obesity among Medicare enrollees; congestive heart failure hospitalization was higher in blacks, Hispanics, and American Indians/Alaska Natives than among whites; and stroke hospitalization was highest in blacks. Age-adjusted mortality from CVD at all ages tended to be highest in blacks. Overall life expectancy was higher in whites (77.2 years) than in blacks (71.8 years) by approximately 5 years. Although disparities by race and ethnicity were prominent, so were differences by sex, educational attainment, SES, and geographic location. Nevertheless, racial and ethnic disparities in CVD and risk factors were pervasive even in 2005.22
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Progress in Reducing Disparities
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In the decade since that assessment, some progress has been made in the quest to improve healthcare quality and reduce or eliminate health disparities.23 Although most health disparities have remained unchanged and some have widened, there is evidence to demonstrate that, in some areas, disparities in the burden of CVD and quality of healthcare have improved. For example, in federally funded research on equity and quality of care in US hospitals, Trivedi et al24 assessed performance rates for 17 objective quality measures covering three conditions (six measures for acute myocardial infarction, four for heart failure, and seven for pneumonia). The performance rates were adjusted for patient- and hospital-level covariates and compared among non-Hispanic white, non-Hispanic black, and Hispanic patients who received care between 2005 and 2010 in acute care hospitals throughout the United States. The adjusted performance rates for the 17 quality measures improved by 3.4 to 57.6 percentage points between 2005 and 2010 for white, black, and Hispanic adults (P < .001 for all comparisons).24 Figure 109–1 shows changes in within-hospital and between-hospital differences from 2005 to 2010. The three measures (in black-white comparisons, panel A) and six measures (in Hispanic-white comparisons, panel B) shown are those with adjusted rate differences that exceeded 5 percentage points in 2005. As the figure demonstrates, significant improvement in performance on quality measures for white, black, and Hispanic adults hospitalized for acute myocardial infarction, heart failure, or pneumonia was accompanied by significant reduction in racial and ethnic disparities in performance rates both within and among US hospitals.24 As another sign of progress, Cohen et al25 reported that among 443 hospitals participating in the Get With the Guidelines–Coronary Artery Disease national quality monitoring and improvement program between January 2002 and June 2007, racial/ethnic differences in individual and composite care were reduced or eliminated. Individual core performance measures included appropriate use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, use of β-blockers at discharge, appropriate use of lipid-lowering drugs, use of smoking cessation counseling, use of aspirin within 24 hours of admission, and use of aspirin at discharge. The composite performance measure of defect-free care was defined as the proportion of patients who received all interventions for which they were eligible.
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Persisting Disparities in Health Behaviors and Cardiovascular Risk Factors
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Although examples of successful reduction or elimination of racial and ethnic disparities in CVD exist, as demonstrated in the studies described above,23,24,25 there are many more instances showing persistence or widening of disparities. For example, Chang et al26 used underlying cause of death data and population estimates from the National Vital Statistics System to calculate age-adjusted death rates for CVD and nine other leading causes of death during 1999 to 2010 in order to explore temporal trends in disparities in death rates by sex and race/ethnicity in the United States during this time period. Substantial declines in age-adjusted mortality for CVD were noted in all race/ethnic groups, as shown in Table 109–4.26 Among the 10 leading causes of death, age-adjusted death rates by sex and race/ethnicity declined from 1999 to 2010 for six causes and increased for four causes; however, sex and racial/ethnic disparities between groups persisted for each year and cause of death.26 For heart disease in 2010, the race/ethnic group with the largest disparity relative to the most favorable group, Asian/Pacific Islander (men 127.3; women 81.4), was the non-Hispanic blacks (men 286.3; women 189.1). Death rates reported were age-adjusted per 100 000 persons based on the 2000 US Census standard population.26 The primary drivers of these persisting disparities included those attributed to cardiovascular health behaviors and risk factors.
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In their estimates of age-adjusted mortality from individuals from 3099 counties in the United States, Vaughan et al27 observed county-level race-sex disparities in heart disease mortality trends. For example, from 1973 to 2010, they observed continual strong declines in 73.2%, 44.6%, 15.5%, and 17.3% of white men, white women, black men, and black women, respectively (Fig. 109–2).27 Additionally, during the period of 1998 to 2010, delayed strong declines occurred in 15.4%, 42.0%, 75.5%, and 76.6% of counties for white men, white women, black men, and black women, respectively (see Fig. 109–2).27 The authors concluded that over the nearly four-decade period of the analysis, patterns of decline in age-adjusted mortality for heart disease differed by race and geography, possibly reflecting disparities in national and local drivers of these declines.27 Better understanding of racial and geographic disparities in the diffusion of heart disease prevention and treatment may allow us to make progress toward achieving racial and geographic equity in heart disease survival.
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Not surprisingly, hypertension remains a major contributor to the persisting large disparity in age-adjusted mortality from heart disease. The age-adjusted hypertension-related mortality in non-Hispanic blacks is significantly higher than the rate seen in non-Hispanic whites and Hispanics.28,29 The disparity is more dramatic when examined by sex (Fig. 109–3).28 For example, in 2013, the death rates per 100,000 population were 51.6 for non-Hispanic black men, but 18.9 for non-Hispanic white men, and 20.0 for Hispanic males.28 The corresponding rates for women were 36.5 for non-Hispanic black women, 15.8 for non-Hispanic white women, and 15.3 for Hispanic women.28
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Prominent racial and ethnic differences are also seen in the prevalence of other CVD risk factors. For example, although overweight and obesity are common in US adults, with a 2011 to 2012 prevalence approaching 70% in adult men, there is a greater prevalence in non-Hispanic whites (73%) and Hispanics (80%) than in non-Hispanic blacks (69%).28 On the other hand, in women, the prevalence of obesity and overweight is much higher in non-Hispanic blacks (82%) than in Hispanics (76%) or non-Hispanic whites.28 Among children and adolescents aged 2 to 19 years, the prevalence of overweight and obesity in the 2011 to 2012 National Health and Nutrition Examination Survey (NHANES) was 31.8%.28 In general, among all children aged 2 to 19 years, the prevalence of overweight and obesity tends to be higher in non-Hispanic black, non-Hispanic white, and Hispanic children than in non-Hispanic Asian children.28 Additionally, within the Hispanic population, important differences in the prevalence of overweight have been demonstrated. For example, Mexican NHANES participants have a higher mean age-adjusted prevalence of being overweight compared with Puerto Ricans and Cubans.30
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The 2011 to 2012 NHANES data have also shown that dyslipidemia, assessed by a total cholesterol of 240 mg/dL or greater, was more prevalent in Hispanic adults (14.2% overall) and non-Hispanic white adults (13.5% overall) than in non-Hispanic black adults (9.8% overall).28 Age-adjusted prevalence estimates from the 2014 National Health Interview Survey (NHIS) in adults demonstrated a greater prevalence of physical inactivity among Hispanics (40.1%) and non-Hispanic blacks (38.3%) than in non-Hispanic whites (26.3%). Finally, the prevalence of current smoking or tobacco use varies significantly by race and ethnicity. Data from the 2014 NHIS in adults aged 18 years and older showed a greater prevalence of current smoking in non-Hispanic black men (21.4%), non-Hispanic white men (19.9%), and Alaska Native men (18.6%) than in Asian men (13.8%) and Hispanic men (13.8%).28 Similarly, non-Hispanic black women (13.4%), non-Hispanic white women (18.3%), and American Indian or Alaska Native women (21.6%) had a greater prevalence of current smoking than Asian women (5.5%) and Hispanic women (7.4%).28
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Racial and ethnic differences have also been demonstrated for estimated heart age, the predicted age of a person's vascular system based on their cardiovascular risk factor profile.31 Using data from Behavioral Risk Factor Surveillance System applied to the sex-specific Framingham risk score models, Yang et al31 compared heart age to chronological age and demonstrated that, on average, predicted heart ages for adult men and women were 7.8 and 5.4 years older than their chronological ages, respectively. Importantly, the prevalence of excess heart age of 5 years or greater (measured as the difference between heart age and chronological age) was greater in non-Hispanic black men (58.7 years) and women (58.9 years) than in other racial/ethnic groups, including non-Hispanic white men (55.3 years) and women (52.5 years).31
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Persisting Disparities in Cardiovascular Diseases and Conditions
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The American Heart Association's Heart Disease and Stroke Statistics provides a comprehensive annual update that includes data on race/ethnicity and health behaviors, risk factors, and specific cardiovascular conditions and diseases as well as their clinical and public health outcomes.28 For example, the 2016 report shows that age-adjusted prevalence estimates for coronary heart disease (CHD) from the 2014 NHIS data are higher in native Hawaiians/Pacific Islanders (6.9%), non-Hispanic whites (5.6%), and non-Hispanic blacks (5.6%) than in Asians (3.3%) and Hispanics (4.9%).28 The reported age-adjusted prevalence for American Indians and Alaska Natives of 6.0% is known to be statistically unreliable. The age-adjusted CHD mortality per 100,000 population in men were higher in non-Hispanic blacks (155.1) and non-Hispanic whites (141.8) than in Hispanics (104.7); the corresponding rates in women were also higher in non-Hispanic blacks (94.7) and non-Hispanic whites (75) than in Hispanics (61.3).28
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There are racial/ethnic disparities in the risk for developing congestive heart failure (CHF).28,32 In the Multi-Ethnic Study of Atherosclerosis (MESA), a cohort study of 6814 participants of four ethnicities—white (38.5%), African American (27.8%), Hispanic (21.9%), and Chinese American (11.8%)—African Americans had the highest incidence rate of CHF, followed by Hispanic, white, and Chinese American participants (incidence rates: 4.6, 3.5, 2.4, and 1.0 per 1000 person-years, respectively).32 In addition, African Americans had the highest proportion of incident CHF not preceded by clinical myocardial infarction (75%) compared with other ethnic groups.32 Importantly, however, differences in the prevalence of hypertension, diabetes mellitus, and socioeconomic factors explained the higher risk of incident CHF among African Americans.32 Data from the Atherosclerosis Risk in Communities (ARIC) cohort showed that incident heart failure per 1000 person-years was higher in African American men (9.1) and women (8.1) than in white men (6.0) and women (3.4); however, these racial differences in heart failure incidence were largely explained by risk factor differences.33 In the ARIC cohort, heart failure case fatality rates 5 years after an incident heart failure hospitalization were significantly higher in African American men (51.8%) and women (46.1%) than in white men (41.2%) and women (35.8%).33
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Additional information on racial and/or ethnic differences in prevalence and mortality of total CVD; prevalence, mortality, and distribution of new and recurrent strokes; mortality of myocardial infarction; and the distribution of physician-diagnosed and undiagnosed diabetes and related mortality are presented for adult men and women in Tables 109–5 and 109–6, respectively. Similarly, the race/ethnic distribution of congenital cardiovascular defects and the distribution of major cardiovascular risk factors in children and youth are presented in Table 109–7. Figure 109–4 shows additional data on racial and ethnic variations in the prevalence of congenital cardiovascular malformations.34
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In contrast to the excess CVD mortality observed in non-Hispanic blacks in the general US population, Kovesdy et al35 reported that, in a large cohort of more than 3 million contemporary US veterans with an estimated glomerular filtration rate ≥ 60 mL/min/1.73 m2, black veterans had lower all-cause mortality, lower incidence of CHD, and a similar incidence of ischemic stroke (Fig. 109–5). These data were derived from multivariable-adjusted Cox models in a nationwide cohort of 547,441 black and more than 2.5 million white veterans receiving care from the US Veterans Health Administration (VHA).35 The findings also do not apply to women because the cohort consisted predominantly of men. Compared with the observations in the general US population, the findings could not be explained on the basis of differences in demographic factors, comorbidity, or socioeconomic characteristics; however, the open access to healthcare and the provision of comprehensive healthcare based on a veteran status within the US VHA may have contributed.35 Kuller and Neaton36 and the VHA study authors and others35,37 caution that the findings may also be attributable to selection for military service and the subsequent use of VHA services among blacks and whites, and thus, the findings may not be generalizable to the overall US population.
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