Heart failure in African Americans: Disparities can be overcome

Genetic polymorphisms

An important caveat in discussing racial differences in heart failure is that “race” is completely arbitrary and is based on sociopolitical rather than scientific or physiologic definitions. Perceived genetic influences are likely to represent complex gene-gene, gene-environment, and gene-drug interactions.

This is especially true for African Americans, who are a markedly heterogeneous group. The US Office of Management and Budget defines “black” or “African American” as having origins in any of the black racial groups of Africa (www.census.gov/2010census/data). Thus, “African American” includes sixth-generation descendants of African slaves, recently immigrated Jamaicans, and black descendants of French and Spanish people.

Most African Americans have some European ancestry. In one study, the estimated proportion of European ancestry ranged from 7% in Jamaicans of African descent to approximately 23% in African Americans in New Orleans.³²

Nevertheless, several polymorphisms associated with the risk of heart failure may provide insight into some of the “race-based” differences in pathophysiology and response to medications and, it is hoped, may eventually serve as the basis for tailored therapy. Genes of interest include those for:

• Beta 1 adrenergic receptor
• Alpha 2c receptor³³
• Aldosterone synthase³⁴
• G protein
• Transforming growth factor beta
• Nitric oxide synthase³⁵
• Transthyrectin.^36,37

Socioeconomic factors and quality of care

Heart failure patients—and especially African Americans—have high rates of hospital readmission, and socioeconomic factors have been implicated. In more than 40,000 patients with heart failure, lower income was a significant predictor of hospital readmission.³⁸ Socioeconomic factors in turn could account for delay in seeking treatment for worsening symptoms, failure to recognize symptoms, limited disease awareness, inadequate access to health care, noncompliance with follow-up appointments, and poor adherence to recommended treatment, all of which are common in African American patients.^38,39

African Americans also report more discrimination from health care providers, have more concerns about blood pressure medications, and are more likely to have misperceptions about high blood pressure (eg, that it is not serious), all of which may interfere with optimal blood pressure control.⁴⁰ Managing heart failure in African Americans should include trying to identify and eliminate barriers to attaining treatment goals.

PREVENTING HEART FAILURE BY REDUCING RISK FACTORS

The American College of Cardiology Foundation and American Heart Association, in their 2013 guidelines, underscored the progressive nature of heart failure by defining four stages of the disease, from stage A (at risk) through stage D (refractory heart failure) (Figure 1).⁴¹ They also emphasized the importance of preventing it.

A thorough clinical assessment, with appropriate assessment for risk factors and intervention at stage A, is critical in preventing left ventricular remodeling and heart failure. These risk factors include hypertension, hyperlipidemia, atherosclerosis, diabetes mellitus, valvular disease, obesity, physical inactivity, excessive alcohol intake, poor diet, and smoking.

Hypertension is especially important in African Americans and requires vigorous screening and aggressive treatment. Antihypertensive drugs should be prescribed early, with a lower threshold for escalating therapy with combinations of drugs, as most patients require more than one.

There is considerable debate about the appropriate blood pressure thresholds for diagnosing hypertension and the optimal target blood pressures in African Americans. The 2014 report of the Joint National Committee recommends a similar hypertension treatment target of 140/90 mm Hg for all patients except older adults (for whom 150/90 mm Hg is acceptable), and no separate target for African Americans.⁴² Previous guidelines from this committee recommended thiazide-type diuretics as first-line therapy for hypertension in African Americans⁴³; the new ones recommend thiazide-type diuretics or calcium channel blockers. However, in those with left ventricular systolic dysfunction, hypertension treatment should include drugs shown to reduce the risk of death in heart failure—ie, angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, hydralazine, nitrates, and aldosterone receptor antagonists.

Salt intake should be reduced to less than 3 g per day (1,200 mg of sodium per day), which has been shown to substantially reduce rates of cardiovascular morbidity and mortality and health care costs.⁴⁴ Since most Americans consume 7 to 10 g of salt per day, strict salt restriction should be encouraged as a preventive measure.

Diabetes should be screened for and treated in African Americans per current American Diabetes Association guidelines.

Dyslipidemia should also be screened for and treated per guidelines.⁴⁵

Smoking cessation, moderation of alcohol intake, and avoidance of illicit drugs should be encouraged. Given that African Americans develop heart failure at a relatively early age, the level of vigilance should be high and the threshold for screening should be low.