Hypertension In African Americans Research Articles

White-coat effect in African-American hypertensives

White-coat effect in African-American hypertensives

Artial natriuretic peptide levels correlate with salt-sensitive hypertension and volume expansion in african-americans

Artial natriuretic peptide levels correlate with salt-sensitive hypertension and volume expansion in african-americans

Epidemiology of hypertension in African American women

To describe the epidemiology of hypertension in U.S. African American women and to highlight priority areas for future research, data from the nationwide surveys of the U.S. National Center for Health Statistics, from selected multicenter studies of the U.S. National Heart, Lung, and Blood Institute, as well as from selected other population-based studies, were reviewed. In 1988 through 1991, an estimated 3 million African American women aged 18 and older had hypertension. Compared with that in U.S. whites, hypertension in black women is characterized by higher incidence, earlier onset, longer duration, higher prevalence, and higher rates of hypertension-related mortality and morbidity. Risk factors for hypertension incidence in black women include obesity and weight gain. The effectiveness of drug therapy of hypertension has been established in black women, and important gains in rates of treatment and control have been accomplished. Nevertheless, rates of hypertension-related mortality for black women remain among the highest in the industrialized nations. Further research on causes and prevention of hypertension in black women is needed. Goals related to prevention and control of hypertension in African Americans for the year 2000 have been established and must be vigorously pursued.

Racial Differences in the Pathogenesis of Hypertension

Hypertension occurs at an earlier age, is more prevalent, and is more often complicated by target organ damage in African-Americans than whites. Reasons for this increased severity of hypertension in African-Americans remain obscure. Based on studies recently completed in their laboratory, the authors propose that greater sympathetic reactivity to stress and a greater prevalence of NaCl sensitivity contribute to the earlier development of hypertension in African-Americans. Using microneurography to record muscle sympathetic nervous system activity, it was found that normotensive blacks manifest greater increases in sympathetic activity to cold stress than normotensive whites. If true of other types of stressors, greater sympathetic reactivity would predispose blacks to the development of hypertension. Using a telemetry-based monitoring system, the authors recently reported that both spontaneously hypertensive rats and normotensive Wistar-Kyoto rats manifest acute sensitivity to high dietary NaCl ingestion, but that the Wistar-Kyoto rats are able to compensate, thereby avoiding sustained increases in blood pressure. Based on these animal studies, it is proposed that elevated nocturnal pressures observed in blacks by other investigators may reflect the greater prevalence of NaCl sensitivity in the black population. As in animal models of NaCl-sensitive hypertension, blacks may retain ingested NaCl, resulting in sustained increases in blood pressure.

A Randomized Controlled Trial of Stress Reduction for Hypertension in Older African Americans

We tested the short-term efficacy and feasibility of two stress education approaches toe the treatment of mild hypertension in older African Americans. This was a randomized, controlled, single-blind trial with 3 months of follow-up in primary care, inner-city health center. Of 213 African American men and women screened, 127 individuals (aged 55 to 85 years with initial diastolic pressure of 90 to 109 mm Hg, systolic pressure of < or = 189 mm Hg, and final baseline blood pressure of < or = 179/104 mm Hg) were selected. Of these, 16 did not complete follow-up blood pressure measurements. Mental and physical stress reduction approaches (Transcendental Meditation and progressive muscle relaxation) were compared with a lifestyle modification education control program and with each other. The primary outcome measures were changes in clinic diastolic and systolic pressures from baseline to final follow-up, measured by blinded observers. The secondary measures were linear blood pressure trends, changes in home blood pressure, and intervention compliance. Adjusted for significant baseline differences and compared with control, Transcendental Meditation reduced systolic pressure by 10.7 mm Hg (P < .0003) and diastolic pressure by 6.4 mm Hg (P <.00005). Progressive muscle relaxation lowered systolic pressure by 4.7 mm Hg (P = 0054) and diastolic pressure by 3.3 mm Hg (P <.02). The reductions in the Transcendental Meditation group were significantly greater than in the progressive muscle relaxation group for both systolic blood pressure (P = .02) and diastolic blood pressure (P = .03). Linear trend analysis confirmed these patterns.(ABSTRACT TRUNCATED AT 250 WORDS)

Hospitalization for Congestive Heart Failure

To determine whether the higher rate of hospitalization among African Americans for congestive heart failure (CHF) could be explained by racial differences in the prevalence of clinical risk factors for CHF. Retrospective cohort study. A large health maintenance organization (HMO). A sample of 64,877 enrollees (27% African American and 73% white) of the Northern California Kaiser Permanente Medical Care Program who took at least one multiphasic health checkup (MHC) at or after the age of 40 years and were free of CHF at that time. First hospitalization with a principal diagnosis of CHF. Among cohort members younger than 60 years at baseline MHC, the age-adjusted risk ratio (RR) (African American/white) for CHF hospitalization was 2.14 for men and 2.73 for women, while for persons 60 years of age and older at MHC, the age-adjusted RR was 1.48 for both sexes. Cox proportional hazards models were used to adjust for risk factors and length of follow-up. In persons aged 60 years and older, the race difference was explained by greater prevalence of hypertension and diabetes in African Americans (RR = 1.12; 95% confidence interval [CI], 0.94 to 1.34 after adjustment for hypertension and diabetes). In those younger than 60 years, findings differed by sex. For men, African-American race was no longer a significant predictor of CHF after adjusting for hypertension, diabetes, left ventricular hypertrophy on electrocardiogram, and body mass index (adjusted RR = 1.16; 95% CI, 0.86 to 1.56). However, among younger women, African Americans continued at increased risk despite adjustment for these variables as well as smoking, plasma cholesterol, renal function, alcohol use, and myocardial infarction (adjusted RR = 1.49; 95% CI, 1.00 to 2.21). In this HMO population, the race differences in first hospitalization for CHF are largely explained by known clinical and behavioral risk factors, although in younger women these risk factors do not completely explain the excess risk among African Americans. These findings highlight the role of hypertension and diabetes in the development of CHF, particularly among African Americans.

Hospitalization for congestive heart failure. Explaining racial differences

<h3>Objective.</h3> —To determine whether the higher rate of hospitalization among African Americans for congestive heart failure (CHF) could be explained by racial differences in the prevalence of clinical risk factors for CHF. <h3>Design.</h3> —Retrospective cohort study. <h3>Setting.</h3> —A large health maintenance organization (HMO). <h3>Patients.</h3> —A sample of 64877 enrollees (27% African American and 73% white) of the Northern California Kaiser Permanente Medical Care Program who took at least one multiphasic health checkup (MHC) at or after the age of 40 years and were free of CHF at that time. <h3>Main Outcome Measures.</h3> —First hospitalization with a principal diagnosis of CHF. <h3>Results.</h3> —Among cohort members younger than 60 years at baseline MHC, the age-adjusted risk ratio (RR) (African American/white) for CHF hospitalization was 2.14 for men and 2.73 for women, while for persons 60 years of age and older at MHC, the age-adjusted RR was 1.48 for both sexes. Cox proportional hazards models were used to adjust for risk factors and length of follow-up. In persons aged 60 years and older, the race difference was explained by greater prevalence of hypertension and diabetes in African Americans (RR=1.12; 95% confidence interval [Cl], 0.94 to 1.34 after adjustment for hypertension and diabetes). In those younger than 60 years, findings differed by sex. For men, African-American race was no longer a significant predictor of CHF after adjusting for hypertension, diabetes, left ventricular hypertrophy on electrocardiogram, and body mass index (adjusted RR=1.16; 95% Cl, 0.86 to 1.56). However, among younger women, African Americans continued at increased risk despite adjustment for these variables as well as smoking, plasma cholesterol, renal function, alcohol use, and myocardial infarction (adjusted RR=1.49; 95% Cl, 1.00 to 2.21). <h3>Conclusions.</h3> —In this HMO population, the race differences in first hospitalization for CHF are largely explained by known clinical and behavioral risk factors, although in younger women these risk factors do not completely explain the excess risk among African Americans. These findings highlight the role of hypertension and diabetes in the development of CHF, particularly among African Americans. (<i>JAMA</i>. 1995;274:1037-1042)

Reduced β2-receptor mediated vasodilation in African Americans

It is well recognized that African Americans have a higher prevalence of cardiovascular disease than White Americans although the underlying mechanisms are not entirely understood. This study was perfumed to evaluate racial differences in the chronotropic and vasodilatory effects of the β-receptor agonist, isoproterenol. We compared cardiovascular responses to intravenous infusion of isoproterenol in 27 African Americans and 27 White men and women. African Americans showed significantly smaller β 2-receptor mediated falls in diastolic pressure than Whites. In contrast, isoproterenol produced similar increases in heart rate in both races. The findings suggest that African Americans have decreased β 2-receptor mediated vasodilatory capacity, and may help explain the higher prevalence of hypertension and cardiovascular disease in African Americans compared to Whites.

D36 - Efficacy and diurnal effects of transdermal clonidine in hypertensive african americans

D36 - Efficacy and diurnal effects of transdermal clonidine in hypertensive african americans

Role of cocaine in end-stage renal disease in some hypertensive African Americans.

During a period of 1 year we observed 12 African American patients who had smoked or sniffed cocaine for several years and presented to inner city hospitals with accelerated hypertension and renal insufficiency. Ten required maintenance dialysis; 1 recovered partially after a brief period of dialysis, and 1 had moderate renal insufficiency. In the absence of striking proteinuria, cardiomegaly or renal shrinkage, the probable diagnosis in most of the patients was primary accelerated hypertension. The clinical history suggested that the habitual use of cocaine had worsened the hypertension, made it more difficult to control or triggered an accelerated phase resulting in renal shutdown. At a time when billions of dollars are being spent on the treatment of end-stage renal disease, the harmful role of cocaine in susceptible individuals requires due attention.

Muscle sympathetic nervous system activity in Black and Caucasian hypertensive subjects

To compare muscle sympathetic nerve activity (MSNA) in age- and weight-matched African-Americans and American Caucasians with primary hypertension. Using microneurography, we compared MSNA at rest and in response to cold-pressor testing and handgrip exercise in 13 hypertensive African-Americans and 12 hypertensive American Caucasians. All subjects were withdrawn from antihypertensive medications for at least 2 weeks before the study. MSNA was recorded from the left peroneal nerve. Resting MSNA was similar in the Blacks and the Caucasians. Increases in muscle efferent activity, mean arterial pressure and heart rate in response to the cold pressure and handgrip exercise were not significantly different in Black and in Caucasian subjects. MSNA, either at rest or in response to certain laboratory stressors, is not different in Black and in Caucasian hypertensive subjects with similar resting blood pressures.

Postpartum Blood Pressure and Insulin Sensitivity in African-American Women With Recent Preeclampsia

Pregnancy-induced hypertension and preeclampsia are relatively common in nulliparous, inner-city, African-American, pregnant women and contribute to considerable maternal, fetal, and neonatal morbidity and mortality in that population. Recently, insulin resistance has been related to the development of hypertension in young African-Americans and hyperinsulinemia and elevated insulin-to-glucose ratios, suggesting insulin resistance, have been demonstrated in women with preeclampsia. To investigate whether insulin resistance existed postpartum and, therefore, independently of the pregnant state, the hyperinsulinemic, euglycemic technique was used 3 to 6 months postpartum to assess insulin sensitivity in 10 young, black, primiparous, inner-city women with recent preeclampsia and seven age-, weight- and body-massindex- matched black women with healthy pregnancies. The age, weight, body-mass index, waist-to-hip ratio, the duration since parturition, and fasting plasma glucose and insulin were similar in the preeclamptic and control groups. During the clamp procedure, the insulin levels and mean diastolic blood pressure and mean arterial pressure were also similar for both groups; however, the mean systolic blood pressure of the preeclamptic group (123 ± 3 mm Hg) was higher than that of the control group (114 ± 2 mm Hg) (P < .05). Insulin- stimulated glucose disposal was not different between the preeclamptic (5.6 ± 0.3 mg/kg/min) and control groups (5.7 ± 0.7 mg/kg/min). This suggests that the elevation in postpartum systolic blood pressure may reflect a persistent abnormality of blood pressure homeostasis which is not associated with insulin resistance. Am J Hypertens 1994; 7:933–936

Stimulated parotid salivary flow rates in normotensive, hypertensive, and hydrochlorothiazide-medicated.

Stimulated parotid salivary flow rates were compared in elderly normotensive, hypertensive, and controlled hypertensive African-Americans, the latter group taking hydrochlorothiazide (HCTZ). The normotensive group consisted of 15 healthy unmedicated subjects with systolic blood pressures of less than 150 mm Hg and diastolic pressures less than 90 mm Hg. The hypertensive group consisted of 10 unmedicated subjects with systolic pressures greater than 160 mm Hg and diastolic pressures greater than 100 mm Hg. The controlled hypertensive group consisted of 20 subjects taking HCTZ (50 mg, daily) with controlled blood pressures similar to the normotensive control group. Stimulated parotid salivary samples were collected from each subject. A 2% citrate solution applied to the dorsum of the tongue was used for stimulation. The results showed no significant differences in stimulated parotid flow rates between normotensive and uncontrolled hypertensive subjects. However, the medicated, controlled hypertensive subjects had a significant reduction of stimulated parotid salivary flow rates compared to both the normotensive and hypertensive groups.

Analysis of two variants of the angiotensinogen gene in essential hypertensive African-Americans.

Two mutations (T174M and M235T) in the angiotensinogen gene have been reported to be associated with hypertension. This study examines the frequency of these mutations among African-American hypertensive patients (n = 109). The allele frequency of the T174M mutation was 4.6% and the frequency of the M235T mutation was 86.7%. The genotypic frequencies agreed with the conditioned Hardy-Weinberg predictions based on allele frequencies. The homozygote wild-type genotype at the T174 site was more frequent than the mutation and occurred at a rate of 91.7%. Conversely, the homozygote for the mutation at the M235 site was more frequent and occurred at a rate of 75.2%. Mutation frequencies for T174M and M235T in this African-American population differ from those previously reported from a white hypertensive population (P = .0058 and P = .0001, respectively). In summary, the representation of the angiotensinogen allele frequencies differ among hypertensive populations.

The Presence of Panic Disorder among African American Hypertensives: A Pilot Study

This pilot study examines the presence ofpanic disorder among an urban African American essential hypertensive sample enrolled at a hospital-affiliatedfamily practice center Symptomatology associated with panic disorder, including the presence of isolated sleep paralysis, is also explored. Panic disorder was more likely to be presentforhypertensives thanfornormotensives. Seven of thepatients with panic disorder and hypertension experienced isolated sleep paralysis.

The Health of African Americans: Special Emphasis on Kidney Disease

W ILLIAM JAMES once said, difference between a good man and a bad man is the choice of a cause. I feel, therefore, that I am in good company with those of you who have committed yourselves to combating kidney disease and hypertension in African Americans. The Department of Health and Human Services (HHS) places a high priority on discovering the root causes of the health disparities that disproportionately affect underserved Americans, and we are committed to eliminating these health disparities. As we will see shortly, kidney disease, hypertension, and end-stage renal disease are major contributors to the disparity in the health of African Americans. I feel this workshop is both appropriate and timely. Thank you for inviting me to address this distinguished group of investigators, and my compliments to the National Institute of Diabetes and Digestive and Kidney Diseases and the National Heart, Lung, and Blood Institute for convening this workshop.

Prevalence of complications and response to different treatments of hypertension in African Americans and white Americans in the U.S..

The aim of this review is to compare the prevalence of complications and response to different treatment for hypertension in African and European Americans. African Americans when compared to European Americans respond less favorably to beta-blockers (BB's) and angiotensin converting enzyme inhibitors (ACEI's). Nevertheless the observed response of African Americans to ACEI's and BB's is significant and these agents are very effective in this subgroup. African American race is not a clinically significant predictor of poor response to any class of antihypertensive therapy and there is little justification to use racial profiling as a criterion for choice of medication. Evidence to restrict or defer usage of BB's and ACEI's in African Americans is lacking. The mortality from hypertensive heart disease, stroke, and the incidence of hypertensive renal disease is higher in African Americans which leads some investigators to postulate that hypertension in African Americans is intrinsically different from whites. They therefore search for a separate etiology and suggest specific approaches to treatment. Awareness of racial differences in hypertension outcomes evolved in the U.S. in an historical context that does not fully appreciate that race is often a surrogate for many social and economic factors that influence health status and health care delivery in the U.S. Poor outcomes in African Americans occur in many diseases including hypertension.

Hypertension in African-Americans.

A considerable disparity exists between African-Americans and US Caucasians in the incidence, severity, and management of hypertension. As a consequence, overall hypertension-related morbidity and mortality rates are at least threefold to fivefold higher in African-Americans than in Caucasians. Alarmingly high frequencies of stroke, end-stage renal disease, congestive heart failure, and left ventricular hypertrophy occur in African-Americans. To bring this crisis under control will require a renewed commitment to expanded research, improved public health measures, and more effective clinical intervention. Current hypertension control programs must be expanded and adequately funded. In addition, primary prevention of hypertension should be strongly recommended for the US population, especially African-Americans.

Hypertensive heart disease in African-Americans.

Hypertensive heart disease is a frequent complication in hypertensive African-Americans because of inadequate high blood pressure control. Moreover, African-Americans may be predisposed to develop LVH earlier in life and more readily than Caucasians, and it may be more malignant. The appearance of both LVH and congestive heart failure are ominous developments in individual patients, and early detection of LVH is mandatory for adequate management and reversal of this complication, if possible. Additional research is needed, and new, sensitive tools for detecting LVH will accelerate such studies. Further investigations are also needed on the reversibility of LVH, preferred antihypertensive agents for accomplishing reversal, and whether expected benefits result.