Hypertension in African Americans:

Hypertension is a major risk factor for cardiovascular and renal morbidity and mortality that is consistently more prevalent and occurs earlier in life in non-Hispanic blacks than in whites.¹ As such, it contributes to racial disparities in mortality.² Moreover, hypertension is inadequately controlled in the majority of affected African Americans: blood pressure is controlled to less than 140/90 mm Hg in only 25% of all African Americans with hypertension and in fewer than 50% of those receiving antihypertensive therapy.¹

In this article, we present strategies to improve blood pressure control in African American patients. We offer a patient-centered approach that can lead to greater patient satisfaction, enhanced compliance, and better health outcomes.

ETIOLOGY OF HYPERTENSION IN AFRICAN AMERICANS

A recent analysis of the National Health and Nutrition Examination Survey (NHANES) data from 1988 to 2000 showed that the prevalence of hypertension among non-Hispanic blacks increased 33.5% during this time.³ Although awareness of hypertension was relatively high throughout this period, control rates remained low (Table 1).

Difficulties in controlling blood pressure in African Americans have been attributed to both biologic and social factors. Although genetic factors may play a role, studies have shown that limited access to medical care, adverse environmental conditions, early life experiences, unhealthy lifestyles, social stressors, and lack of social support are important associated factors.⁴ Researchers have suggested that a sociocultural model of hypertension be used for African Americans-one in which blood pressure elevation varies with socioeconomic factors and psychosocial stressors.⁵

TREATMENT OVERVIEW

A large body of literature documents the efficacy of lifestyle modification on blood pressure control in African Americans. The PREMIER clinical trial,⁶ the Dietary Approaches to Stop Hypertension (DASH) trial,⁷ the African American Study of Kidney Disease and Hypertension (AASK) trial,⁸ and the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack trial (ALLHAT)⁹ show that lifestyle modification and drug therapy can be effective in African Americans. Intervention studies that involved medications, health education, psychosocial counseling, and nonpharmacologic therapies have also shown efficacy-regardless of approach, setting, or profession of the person who implemented the intervention (ie, nurse, health educator, community health worker, or pharmacist).^7,10-15

In all patients with hypertension, there are 3 main clinical goals:

• Establish a target blood pressure.
• Identify the appropriate lifestyle modifications.
• Determine appropriate pharmacologic interventions.

Clinical goal #1: Clinical evaluation and establishment of target blood pressure. The first potential barrier to effective management of hypertension in African Americans may be the failure to diagnose hypertension early and to treat it aggressively.¹⁶

In its Seventh Report, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) recently revised its classification of hypertension.¹⁷ JNC 7 now recognizes "high-normal" blood pressures as "prehypertension" and categorizes high blood pressure into 2 stages (Table 2). The identification of high-normal blood pressure is especially important in African Americans because hypertension tends to develop early in these patients.

Include in the clinical evaluation of any patient with blood pressure categorized as "prehypertensive" or higher:

• Assessment of standard cardiovascular risks.
• Identification of secondary causes of hypertension and evidence of target-organ damage.
• Assessment of comorbidities.
• Medical history, including family history.
• Review of current medications.
• Exploration of health-related behaviors (smoking, alcohol consumption, physical activity, dietary habits, illicit drug use).
• Physical examination (including weight and body mass index or waist circumference, as indicated).
• Laboratory studies (fasting lipid profile, measurement of serum creatinine and plasma glucose levels, urinalysis [including testing for microalbuminuria], and ECG).

JNC 7 recommends a goal blood pressure of less than 140/90 mm Hg-and less than 130/80 mm Hg in patients with diabetes or chronic kidney disease.¹⁷

In the AASK trial, the effects of 2 levels of blood pressure control on kidney function in patients with hypertension were compared. Among participants randomized to a goal blood pressure of less than 140/90 mm Hg, the percentage of those who achieved this goal increased from 21.5% to 41.8% after 14 months. However, among participants randomized to a goal blood pressure of less than 125/75 mm Hg, the percentage of those who achieved blood pressures less than 140/90 mm Hg increased from 20% to 78.9%.¹⁸ Thus, blood pressure control is possible even in patients whose blood pressure is considered to be the most difficult to control.

Clinical goal #2: Identification of appropriate lifestyle modifications. Obesity, high sodium and low potassium intake, and inadequate physical activity have been identified as barriers to cardiovascular health in many African Americans.¹⁹ Therefore, it is important to educate and counsel patients about lifestyle modifications. Make recommendations that are realistic, specific, and tailored to the individual patient. Table 3 lists several effective lifestyle modifications and the associated decreases in blood pressure.

Counsel all African Americans to follow low-sodium, DASH diets that are rich in fruits, vegetables, fiber, and low-fat dairy products and that are low in saturated and total fat. The DASH diet was found to be beneficial to all study participants with hypertension, but it was most effective in African Americans with high blood pressure.⁷ In all populations, there appears to be an association between salt intake and blood pressure; this link may, in turn, be associated with obesity.¹⁹

Encourage patients to increase aerobic activity (eg, brisk walking) to 30 minutes per day, most days of the week. In addition, advise all patients to reduce their alcohol consumption and to stop smoking.

Clinical goal #3: Determination of appropriate pharmacologic interventions. For most patients, combination antihypertensive therapy is required to reach target blood pressure goals.¹⁷ In the AASK trial, 2 or 3 drugs were needed to reduce blood pres-sure in African Americans with hypertension and mild to moderate renal dysfunction.⁸

All classes of antihypertensive agents have been shown to lower blood pressure in African Americans.¹⁹ Therefore, race should not be used as a reason to avoid certain classes of antihypertensives in this patient population. When used as monotherapy, β-blockers, angiotensin-converting enzyme (ACE) inhibitors, and angiotensin II receptor blockers (ARBs) may lower blood pressure to a lesser degree in African Americans than in whites. Thiazides and calcium channel blockers (CCBs) may have a greater antihypertensive effect in African Americans than other classes of drugs.

If monotherapy is ineffective, a combination of low doses of 2 antihypertensive agents has been shown to reduce diastolic blood pressure by 4 to 6mm Hg more and systolic pressure by 8 to 11 mm Hg more than monotherapy at the highest recommended dosage.¹⁹ Effective combinations include:

• β-Blocker and diuretic.
• ACE inhibitor and diuretic.
• ACE inhibitor and CCB.
• ARB and diuretic.

PATIENT AND PHYSICIAN BARRIERS TO HYPERTENSION CONTROL

Both patient and physician barriers contribute to the overall low rates of hypertension control as well as to racial disparities in control.

Practical and logistic issues that impede access to health care (such as lack of transportation, health insurance, or financial resources; inability to take time off from work; and lack of a usual source of medical care) contribute to the high prevalence of uncontrolled hypertension among patients who are members of ethnic minorities or who are from lower socioeconomic groups.^20-22 However, studies show that even among patients who receive regular care, blood pressure control remains suboptimal; this suggests that patient noncompliance with recommended therapies and physician practice patterns may also play a role.^23,24

Factors that appear to significantly influence patients' compliance include knowledge about their medical condition, confidence in their ability to comply with recommended behaviors, perceptions about health and the benefits of therapy or recommended behaviors, cultural beliefs, availability of social support, depression and substance abuse problems, and the complexity of a regimen.^25-30 Some patients, for example, may not adhere to their prescribed medication regimen because they do not perceive a need for medical therapy.

Physician practice patterns that may contribute to ineffective antihypertensive therapy include deficiencies in knowledge, lack of effectiveness in counseling patients about behavioral and lifestyle changes, lack of awareness of the health care provider's role in improving patient compliance with medication regimens and lifestyle modifications, infrequent patient follow-up, and poor communication styles.^31,32

IMPORTANCE OF EFFECTIVE PATIENT-PHYSICIAN COMMUNICATION

To overcome many patient and physician barriers and to achieve clinical goals, effective communication is of paramount importance. For patients who are members of an ethnic minority, physician-patient communication plays a key role in the establishment of a therapeutic relationship.

Barriers created by poor communication. A recent survey of more than 1800 primary care patients found that African American patients and those from other minority groups described their physicians as having a participatory decision-making style less frequently than white patients did, particularly when physician and patient belonged to different racial groups.³³ Another study found that members of racial and ethnic minority groups perceived physicians' trustworthiness and style of interaction less positively than whites.³⁴

Physicians' negative perceptions of patients from ethnic minority groups may contribute to these patients' mistrust and negative views. Researchers have found that physicians were more likely to view African American patients and those from lower socioeconomic groups as less educated, less likely to be compliant, less likely to pursue physically active lifestyles, and more likely to engage in high-risk health behaviors.³⁵

Overcoming barriers through patient-centered communication. Awareness of the previously mentioned perceptions-and the barriers they create-is a first step for primary care physicians who want to effectively engage their African American patients in the management of their hypertension. Patient-centered communication strategies can help dispel negative perceptions.

Patient-centered care is defined as health care that is closely congruent with and responsive to patients' values, needs, and preferences.³⁶ Characteristics of patient-centered visits include:

• More questions from the patient and more information from the physician.
• More psychosocial and emotional statements from the physician than biomedical statements.
• Less verbal dominance of the discussion by the physician.

Effective physician-patient communication is associated with im-provements in patient satisfaction, compliance, and health outcomes.³⁷ Strong evidence links patient-centered communication to improvements in such markers of disease control as hemoglobin A_1c and blood pressure, to enhanced reports of physical and emotional health status, to improved functioning, and to better pain control.^31,38,39

Visits in which the physician uses a participatory decision-making style have been associated with higher levels of patient satisfaction.^33,40 Recent studies of patient-physician communication in primary care show that the highest levels of patient satisfaction are associated with communication patterns characterized by psychosocial exchange and an almost equal distribution of patient and physician talk.^41-43 In addition, a meta-analysis that correlated communication styles in medical visits with patient outcomes concluded that 3 dimensions of communication (information giving, interpersonal sensitivity, and partnership building) were consistently associated with patient satisfaction, compliance, and recall of information.⁴⁴

Elements of effective patient-centered communication. We recommend the following patient-centered communication strategies (also summarized in Table 4):

• Explore the patient's sociocultural influences, health beliefs, and health-related behaviors. This important step can help you understand the patient's perspective on his or her medical problem, including its social, emotional, and cultural context. Use open-ended questions that span biomedical, psychosocial, therapeutic, and lifestyle domains. Open-ended questions may be followed by more directed probes to help confirm or rule out specific hypotheses. Active listening skills are also important. These include verbal and nonverbal indicators of interest in what the patient is saying.

• Educate and counsel the patient about hypertension and its cardiovascular and renal complications and about management strategies (lifestyle modifications and antihypertensive medications). Education provides factual information about the patient's medical condition, treatment, tests and procedures, and lifestyle changes that promote self-care and prevention; it can also provide psychosocial information that links emotions and social relationships with the patient's health.

Counseling differs from education in that its purpose is to motivate, encourage, and persuade the patient to engage in recommended behaviors. Common topics for counseling include compliance with medication regimens, lifestyle changes, self-care, and psychosocial issues.

Education and counseling are most effective when offered in small doses, presented in easily understood language, and accompanied by frequent checks for patient understanding and readiness to receive the information.

• Build rapport with the patient. Rapport-building skills focus on the emotional aspects of the patient-physician relationship. The behaviors involved include showing empathy and concern, legitimating patients' emotional responses, and providing reassurance. The goal of all rapport-building skills is to respond effectively to patients' emotions as they face uncertainties and challenges related to their health condition.

• Establish a partnership in decision making so that the patient's perspective is taken into consideration. Physicians can involve the patient in the medical dialogue and in decision making by talking less, listening more, asking the patient's opinion, checking for patient understanding, and encouraging the patient to talk and ask questions. Nonverbal cues-such as eye contact, leaning forward, and nodding-can also facilitate patient involvement and partnership in decision making.

References:

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