Managing hypertension in African-American patients

Relationship Between Risks for Obstructive Sleep Apnea, Resistant Hypertension, and Aldosterone Among African American Adults in the Jackson Heart Study

BACKGROUND

African Americans have a higher prevalence of resistant hypertension compared with Caucasians. Racial differences in obstructive sleep apnea (OSA) and increased aldosterone level may explain the racial disparity in resistant hypertension prevalence. Therefore, the purpose of this study is to investigate if aldosterone level and hypertension status differ by risks for OSA (e.g., obesity, loud snoring, and daytime sleepiness) and how aldosterone level varies with hypertension severity and control among African Americans.

METHODS

A cross-sectional analysis was performed using baseline data on 5,052 African American adults in the Jackson Heart Study to investigate the relationships of interest using multivariable linear and multinomial logistic regression models adjusted for potential confounders. Risks for OSA were defined by a "risk score" consisting of the number of risks for OSA.

RESULTS

Of the 5,052 participants, 623 had no risks for OSA. Body mass index was the highest among those with a risk score of 6. About 39% of the sample had no hypertension, 29% had controlled hypertension, 26% had uncontrolled hypertension, and 6% had resistant hypertension. Higher odds of having uncontrolled hypertension or resistant hypertension were present in those with a higher risk score compared with those without risks for OSA. Log-aldosterone level increased with each additional risk for OSA (P-trend <0.05). Similarly, log-aldosterone also increased with more severe hypertension (P-trend <0.001). The highest aldosterone level was found in those with resistant hypertension that was inadequately controlled with medications.

CONCLUSIONS

Risks for OSA were positively associated with resistant hypertension and higher aldosterone level in African American adults.

Severity of systemic sclerosis-associated pulmonary arterial hypertension in African Americans

African Americans (AA) with systemic sclerosis (SSc) have a worse prognosis compared to Americans of European descent (EA). We conducted the current study to test the hypothesis that AA patients with SSc have more severe disease and poorer outcomes compared to EA patients when afflicted with pulmonary arterial hypertension (PAH). We studied 160 consecutive SSc patients with PAH diagnosed by right heart catheterization, comparing demographics, hemodynamics, and outcomes between AA and EA patients. The cohort included 29 AA and 131 EA patients with similar baseline characteristics except for increased prevalence of diffuse SSc in AA. AA patients had worse functional class (FC) (80% FC III-IV vs 53%; p = 0.02), higher brain natriuretic peptide (NT-pro-BNP) (5729 ± 9730 pg/mL vs 1892 ± 2417 pg/mL; p = 0.02), more depressed right ventricular function, a trend toward lower 6-minute walk distance (263 ± 111  m vs 333 ± 110  m; p = 0.07), and worse hemodynamics (cardiac index 1.95 ± 0.58 L/min/m vs 2.62 ± 0.80 L/min/m; pulmonary vascular resistance 10.3 ± 6.2 WU vs 7.6 ± 5.0 WU; p  < 0.05) compared with EA patients. Kaplan-Meier survival estimates for AA and EA patients, respectively, were 62% vs 73% at 2 years and 26% vs 44% at 5 years (p  > 0.05). In conclusion, AA patients with SSc-PAH are more likely to have diffuse SSc and to present with significantly more severe PAH compared with EA patients. AA patients also appear to have poorer survival, though larger studies are needed to investigate this association definitively.

Antihypertensive and metabolic effects of Angiotensin receptor blocker/diuretic combination therapy in obese, hypertensive African American and white patients

A clinical trial showed comparable blood pressure (BP) lowering by valsartan/hydrochlorothiazide and amlodipine/hydrochlorothiazide in obese hypertensive patients. Relative to amlodipine/hydrochlorothiazide, valsartan/hydrochlorothiazide reduced the hyperglycemic response to glucose challenge. An objective of this post hoc analysis was to determine whether this benefit extended to African Americans and whites. Treatments (160/12.5 mg of valsartan/hydrochlorothiazide force titrated to 320/25 mg of valsartan/hydrochlorothiazide at week 4 or 12.5 mg of hydrochlorothiazide force titrated to 25 mg of hydrochlorothiazide at week 4 with 5 and 10 mg of amlodipine added at weeks 8 and 12, respectively) were administered once daily. Both treatments reduced clinic BP from baseline to all visits (P < 0.0001), regardless of race/ethnicity (126 African Americans, 212 whites). In African Americans, there were no significant between-treatment differences in clinic or ambulatory BP lowering at weeks 8 or 16. Whites responded better to valsartan/hydrochlorothiazide. In both racial/ethnic subgroups, the addition of valsartan but not amlodipine mitigated the hyperglycemic response to hydrochlorothiazide through enhanced insulin secretion. Valsartan/hydrochlorothiazide was as effective as amlodipine/hydrochlorothiazide was in reducing BP in obese, hypertensive African Americans and better than amlodipine/hydrochlorothiazide in whites. In both racial/ethnic subgroups, the addition of valsartan to hydrochlorothiazide reduced the negative metabolic effects associated with thiazide therapy.

The Disproportionate Impact of Hypertensive Cardiovascular Disease in African Americans: Getting to the Heart of the Issue

The prevalence of hypertension in African Americans is among the highest in the world. Persons in this group develop hypertension at a younger age than non-African Americans and develop more severe complications, including stroke, cardiovascular disease, and renal failure. The factors that impart this high risk to this population remain poorly understood and, undoubtedly, environmental factors overshadow genetic predisposition. While identifying the pathophysiologic and environmental factors that contribute to ethnic disparity in disease is important, finding a long-term solution is crucial. Steps that can have an important impact on health outcomes of African Americans are presently available. Awareness of ethnicity as a risk factor for hypertension can allow health care providers to identify persons who are likely to benefit most from early, aggressive intervention. Modifiable factors such as smoking, diet, and sedentary lifestyle, as well as undertreatment of hypertension by physicians, can be targeted immediately.

Executive summary of the African-American Initiative

The roundtable discussion, "Managing Cardiovascular Disease in African Americans: Emerging Strategies for Optimizing Care, " was convened to review the evidence that supports best practices for the management of cardiovascular disease and its complications in African Americans. Treatment guidelines are reviewed, as is the clinical evidence supporting the use of diuretics, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and beta-blockers. The ultimate goals of this work are to improve the understanding of the links among hypertension, diabetes, the metabolic syndrome, and cardiovascular disease, all of which disproportionately affect African Americans, and to increase physician awareness of the unique impact of these conditions in the often underserved African-American population.