Gender and Ethnic Disparities in Cardiovascular Disease

By Carolina Gongora, M.D.

About 600,000 people die of heart disease in the United States every year, corresponding to 1 in 4 deaths. Cardiovascular disease (CVD) is the No. 1 cause of death in both women and men and is highest in the South and lowest in the West. Unfortunately, half of Americans have at least one of the recognized risk factors for CVD, including dyslipidemia, hypertension or smoking. Despite this being the case across ethnicities and genders, there are differences among different groups regarding prevalence, treatment and outcomes.

According to the National Health Interview Survey in 2012, more men than women have have been diagnosed with coronary artery disease (CAD) or hypertension (HTN).  Asians adults were less likely to have been diagnosed with CAD than whites. Asian adults and whites were less likely to be diagnosed with HTN than black adults. Poverty level is inversely associated to any type of heart disease, HTN or stroke.[1]

Ethnic Disparities

In 2002, the Institute of Medicine (IOM) reported remarkable disparities in healthcare quality in racial and ethnic minorities. These observations helped encourage the development of new strategies to improve accessibility and quality of healthcare for these minorities. A decade later, quality of care has improved for most Americans, however significant disparities persist.

By 2013, similar proportion of whites, African Americans, Hispanics and American Indians had heart disease, around 10 percent. However, in terms of hypertension, there are significant differences. In whites, Hispanics and American Indians, the prevalence of hypertension and stroke is similar, around 20-25 percent and 2 percent, respectively. But in African Americans, the prevalence of hypertension and stroke is significantly higher, 32 percent and 3.6 percent, respectively. Of these hypertensive patients, only around 50 percent were controlled, 75 percent treated and 15 percent undiagnosed.[1]  In Hispanics, hypertension prevalence is similar to whites, but only one third is controlled compared to 50 percent in whites.[2]

Regarding risk factors for HD, obesity rates are highest in Mexican American males and black women. Hypercholesterolemia is higher in white and Mexican American men and white women. Hospitalization for congestive heart failure and stroke is higher in women and highest in the southeastern part of the country. Life expectancy is higher for whites than blacks by approximately 5 percent.

Among modifiable risk factors, while smoking is higher in white women, other factors such as obesity and physical inactivity are much more common among African American and Hispanic women. It seems that Puerto Rican women have the highest rates of hypertension, obesity, smoking and dyslipidemia compared to the rest of Central and South America.[3]

Racial minorities have been observed to receive less timely evidenced-based interventions (angioplasty, PCI and CABG) and to have worse outcomes after these interventions.[4]

Another important difference worth mentioning among racial and ethnic groups is healthcare coverage. As expected, patients without adequate health insurance are more likely to experience poor clinical outcomes and have higher mortality. Minorities make a significant proportion of the low income and uninsured population and also rely more on acute hospital care than consistent preventive care with a primary care provider.[5]

Gender-Specific Disparities

Presentation and diagnosis of ischemic heart disease (IHD) in women. Women present more frequently than men with chest pain without having obstructive CAD. In the setting of MI, women less often report chest pain and diaphoresis and more often complain of back or jaw pain, palpitations, lightheadedness or loss of appetite. This atypical presentation in women has been linked to the delay in diagnosis and delivery of life-saving treatment strategies, with poorer outcomes.

Before 75 years of age, a higher proportion of a CVD caused by coronary artery disease occur in men than women, and a higher proportion of strokes happen in women than in men.[6, 7]

When evaluating a woman for IHD, the determination of a woman’s risk status will guide the selection of appropriate diagnostic tests. In general, premenopausal women 50 or younger, with no CHD equivalent conditions such as diabetes or peripheral artery disease, are considered to be at low risk. Women in their 50s are classified as low or intermediate risk based on level of functional capacity, with lower functional capacity conferring higher risk. Women in their 60s are considered intermediate risk, and women 70 or older are considered high risk. The presence of comorbidities and multiple other risk factors may adjust the assessment of risk up to one category.[8]

Specific risk factors related to women. Despite the decline in ischemic heart disease in both men and women, more women still die from CVD than men. Some data indicates the prevalence of CVD in women between 35 and 54 years old is increasing.

The traditional Framingham Risk Score is now known to underestimate women’s CV risk. It classifies 90 percent of women as low risk. The impact of some traditional risk factors differs between men and women. Hypertension is rising similarly in men and in women. However, premenopausal women are at higher risk of end-organ damage than men, and after menopause the prevalence of HTN is higher in women.[9]

Women are at higher risk of left ventricular hypertrophy and symptomatic heart failure with preserved ejection fraction. Women who smoke and those with metabolic syndrome have 25 percent more risk of CV events than men. [10] The impact of developing diabetes in middle age is higher in women than men.[11] Another significant difference is the lack of aspirin benefit is preventing ACS in women before 65 years old compared to same age men.[12]  And fewer women than men report performing the recommended 150 minutes of exercise each week.

Besides the traditional risk factors, there are risk factors that are unique to women, like pregnancy-related complications, depression, anxiety, hormonal factors and autoimmune diseases that are more common in women than men.

Women with PCOS have a higher prevalence of metabolic syndrome, diabetes, obesity and HTN. Women with PCOS have elevated coronary calcium score compared to matched controls.[13]

Pregnancy is considered a stress test. When a woman fails this stress test, complications like preeclampsia, eclampsia, gestational diabetes (GD) and preterm delivery occur. These complications are associated with an increased risk of CVD. Preeclampsia triples the risk of CV events and quadruples the risk of future HTN. [14]  GD increases the risk of developing diabetes melliyus (DM) later in life.[15] In fact, the 2011 ACC guidelines included complications during pregnancy as risk factor for CVD.

Systemic rheumatologic diseases, systemic lupus erythematosus (SLE) and rheumatoid arthritis are more common in women and are associated with a 50 percent higher risk of CAD than non-affected women.[16, 17]

Incidence of IHD increases after menopause, likely due to the drop in estrogen and increase in testosterone. Within a year of menopause, cholesterol levels increase. The beneficial effects of hormone replacement therapy are controversial, and currently hormone replacement therapy is not recommended for CVD prevention.[18] Chronic use of oral contraceptives (OCPs) in women who smoke increase by seven fold the risk of CV or thrombotic events and stroke. In women with history of HTN, progestin-only OCPs are recommended over combined OCPs.

Depression, mainly in younger women, and migraine, both more common in women than men, have been associated with increased risk of IHD and stroke. Moderate to severe depression doubles the risk of heart attack in the next 2 years and increases the risk of death. For this reason the American Heart Association (AHA) recommends women be screened and treated for depression. Migraines with aura are associated with ischemic stroke, CV events and death due to ischemic CVD, effects that are potentiated significantly by smoking and oral contraceptive use.  Migraine without aura was not associated with increased risk of any CVD event.

Statistical data. Cardiovascular disease mortality trends in the U.S. showed a decline exclusively in men until 2000. However, since 2000 we have seen a 40 percent decline in CVD-related mortality in women. Despite this decline, women still have a high prevalence of CVD, and studies suggest that women have worse outcomes after MI and a higher incidence of heart failure compared to men.

Traditionally, research studies have excluded women, and in clinical trials women are underrepresented. This situation is changing, and recent evidence shows that there are differences in the presentation, pathophysiology, diagnosis and treatment of CAD for women versus men. Despite sharing many of the traditional CHD risk factors, women have unique risk factors and mechanisms of the disease compared to men.

Some studies have shown that close to half of women with abnormal noninvasive tests do not have flow-limiting coronary stenosis at angiography. However, these women still have a 9 percent occurrence of death or myocardial infarction and have worse prognosis than men. Women with stable ischemic heart disease, despite having less severe obstructive coronary artery disease compared to men have twice the mortality and morbidity.[19]

Women with angina undergo exercise stress testing less frequently than men and are less likely to be referred to angiography and have coronary revascularization. Also, aspirin, ACE inhibitors, statin and heparin are used significantly less in women than in men.[20] In addition, six months after a myocardial infarction, women are less likely to achieve target blood pressure, LDL and hemoglobin A1c.

Despite the decline in women’s heart disease since 2000, the burden of disease and risk factor prevalence remain high and the evidence still suggests that women with myocardial infarction have a worse outcome and higher incidence of congestive heart failure after MI compared to men. Marked reductions in cardiovascular mortality in women are the result of an increase in professional awareness, a greater focus on women’s cardiovascular risk and application of evidence-based treatments for established coronary heart disease.

Racial and ethnic disparities continue to persist in healthcare and treatment, and the increasing prevalence of CV risk factors makes these disparities more difficult to overcome. Treatment options, outcomes and healthcare coverage are still unequal in racial/ethnic minorities compared to whites. Efforts to apply evidence-based care and improve quality should continue in order to reduce the gap between women and men and among racial/ethnic groups.

References

 

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