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

Developing a Sustainable Cardiovascular Disease Research Strategy in Tanzania Through Training: Leveraging From the East African Centre of Excellence in Cardiovascular Sciences Project

Introduction

Cardiovascular disease (CVD) contribute the largest mortality burden globally, with most of the deaths (80% of all deaths) occurring in low and middle-income countries (LMICs), including Tanzania. Despite the increasing burden, to date, CVD research output is still limited in Tanzania, as it is for many sub-Saharan Africa (SSA) countries. This trend hinders the establishment of locally informed CVD management and policy changes. Here, we aim to review the existing gaps while highlighting the available opportunities for a sustainable CVD research strategy in Tanzania.

Methods

A rapid review of available literature on CVD research in SSA was conducted, with emphasis on the contribution of Tanzania in the world literature of CVD. Through available literature, we identify strategic CVD research priorities in Tanzania and highlight challenges and opportunities for sustainable CVD research output.

Findings

Shortage of skilled researchers, inadequate research infrastructure, limited funding, and lack of organized research strategies at different levels (regional, country, and institutional) are among the existing key bottlenecks contributing to the low output of CVD research in Tanzania. There is generally strong global, regional and local political will to address the CVD epidemic. The establishment of the East African Centre of Excellence in Cardiovascular Sciences (EACoECVS) offers a unique opportunity for setting strategies and coordinating CVD research and training for Tanzania and the East African region.

Conclusion

There is a light of hope for long-term sustainable CVD research output from Tanzania, taking advantage of the ongoing activities and plans for the evolving EACoECVS. The Tanzanian experience can be taken as a lesson for other SSA countries.

Association of Sickle Cell Trait With Incidence of Coronary Heart Disease Among African American Individuals

IMPORTANCE

The incidence of and mortality from coronary heart disease (CHD) are substantially higher among African American individuals compared with non-Hispanic White individuals, even after adjusting for traditional factors associated with CHD. The unexplained excess risk might be due to genetic factors related to African ancestry that are associated with a higher risk of CHD, such as the heterozygous state for the sickle cell variant or sickle cell trait (SCT).

OBJECTIVE

To evaluate whether there is an association between SCT and the incidence of myocardial infarction (MI) or composite CHD outcomes in African American individuals.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included 5 large, prospective, population-based cohorts of African American individuals in the Women's Health Initiative (WHI) study, the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, the Multi-Ethnic Study of Atherosclerosis (MESA), the Jackson Heart Study (JHS), and the Atherosclerosis Risk in Communities (ARIC) study. The follow-up periods included in this study were 1993 and 1998 to 2014 for the WHI study, 2003 to 2014 for the REGARDS study, 2002 to 2016 for the MESA, 2002 to 2015 for the JHS, and 1987 to 2016 for the ARIC study. Data analysis began in October 2013 and was completed in October 2020.

EXPOSURES

Sickle cell trait status was evaluated by either direct genotyping or high-quality imputation of rs334 (the sickle cell variant). Participants with sickle cell disease and those with a history of CHD were excluded from the analyses.

MAIN OUTCOMES AND MEASURES

Incident MI, defined as adjudicated nonfatal or fatal MI, and incident CHD, defined as adjudicated nonfatal MI, fatal MI, coronary revascularization procedures, or death due to CHD. Cox proportional hazards regression models were used to estimate the hazard ratio for incident MI or CHD comparing SCT carriers with noncarriers. Models were adjusted for age, sex (except for the WHI study), study site or region of residence, hypertension status or systolic blood pressure, type 1 or 2 diabetes, serum high-density lipoprotein level, total cholesterol level, and global ancestry (estimated from principal components analysis).

RESULTS

A total of 23 197 African American men (29.8%) and women (70.2%) were included in the combined sample, of whom 1781 had SCT (7.7% prevalence). Mean (SD) ages at baseline were 61.2 (6.9) years in the WHI study (n = 5904), 64.0 (9.3) years in the REGARDS study (n = 10 714), 62.0 (10.0) years in the MESA (n = 1556), 50.3 (12.0) years in the JHS (n = 2175), and 53.2 (5.8) years in the ARIC study (n = 2848). There were no significant differences in the distribution of traditional factors associated with cardiovascular disease by SCT status within cohorts. A combined total of 1034 participants (76 with SCT) had incident MI, and 1714 (137 with SCT) had the composite CHD outcome. The meta-analyzed crude incidence rate of MI did not differ by SCT status and was 3.8 per 1000 person-years (95% CI, 3.3-4.5 per 1000 person-years) among those with SCT and 3.6 per 1000 person-years (95% CI, 2.7-5.1 per 1000 person-years) among those without SCT. For the composite CHD outcome, these rates were 7.3 per 1000 person-years (95% CI, 5.5-9.7 per 1000 person-years) among those with SCT and 6.0 per 1000 person-years (95% CI, 4.9-7.4 per 1000 person-years) among those without SCT. Meta-analysis of the 5 study results showed that SCT status was not significantly associated with MI (hazard ratio, 1.03; 95% CI, 0.81-1.32) or the composite CHD outcome (hazard ratio, 1.16; 95% CI, 0.92-1.47).

CONCLUSIONS AND RELEVANCE

In this cohort study, there was not an association between SCT and increased risk of MI or CHD in African American individuals. These disorders may not be associated with sickle cell trait-related sudden death in this population.

Richard Allen Williams, M.D.: a Career Fighting Disparities and Fostering Equity

This is a literature review where we acknowledge Richard Allen Williams, the first African American physician to win the John P. McGovern Compleat Physician Award, and recognize his achievements in race and ethnicity in healthcare. There have been significant advances in the diagnosis and treatment of cardiovascular disease; however, racial disparities continue to create inequity in the medical community especially for African Americans. Dr. Williams founded the Association of Black Cardiologists (ABC) in 1974 to address the misperception about, and the misdiagnosis and maltreatment of African American patients. He emphasized the importance of diversity and the non-biased approach to the treatment of all communities. This literary review further explores current racial disparities African Americans face during the COVID-19 pandemic. Granted that Dr. Williams’ win is a step towards progress and change, there is much to be done to conquer the cultural divide in healthcare.

Opportunities for the Advanced Practice Nurse to Enhance Hypertension Knowledge and Self-management Among African American Women

PURPOSE

Despite increased awareness and the advent of methods to manage the disease, hypertension is poorly controlled among African American women. This study explored hypertension knowledge and blood pressure in a sample of African American women.

DESIGN

A descriptive, cross-sectional design was used to collect survey data on hypertension knowledge.

METHODS

African American women attending a church conference were invited to complete a questionnaire, which included the Check Your High Blood Pressure Prevention IQ survey, and had their blood pressures measured.

RESULTS

Of the 151 women who participated, 62% were diagnosed with hypertension. Many of the women, even those not diagnosed with hypertension, had elevated blood pressures. Although the average scores showed that the women scored well on the survey, there were 4 items on the survey that a percentage of the women had difficulty with: questions about (1) stress as a cause of hypertension, (2) symptoms associated with high blood pressure, (3) whether hypertension could be cured, and (4) the amount of exercise needed to help reduce blood pressure.

CONCLUSION

Despite efforts to increase awareness and control of hypertension, considerable misconceptions about the disease were found in this sample of African American women. To improve self-management of hypertension among this group, advanced practice nurses need to directly address these misconceptions.

Genetics of transfusion recipient alloimmunization: can clues from susceptibility to autoimmunity pave the way?

The search for genetic determinants of alloimmunization in sickle cell disease transfusion recipients was based on two premises: i) that polymorphisms responsible for stronger immune and/or inflammatory responses and hemoglobin β(S) mutation were co-selected by malaria; and ii) that stronger responder status contributes to development of lupus. We found a marker of alloimmunization in the gene encoding for Ro52 protein, also known as Sjögren syndrome antigen 1 (SSA1) and TRIM21. Surprisingly, the nature of the association was opposite of that with lupus; the same variant of a polymorphism (rs660) that was associated with lupus incidence was also associated with induction of tolerance to red blood cell antigens during early childhood. The dual function of Ro52 can explain this apparent contradiction. We propose that other lupus/autoimmunity susceptibility loci may reveal roles of additional molecules in various aspects of alloimmunization induced by transfusion as well as during pregnancy.

Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

The aim of this updated guideline is to provide comprehensive and timely evidence-based recommendations on the prevention of future stroke among survivors of ischemic stroke or transient ischemic attack. The guideline is addressed to all clinicians who manage secondary prevention for these patients. Evidence-based recommendations are provided for control of risk factors, intervention for vascular obstruction, antithrombotic therapy for cardioembolism, and antiplatelet therapy for noncardioembolic stroke. Recommendations are also provided for the prevention of recurrent stroke in a variety of specific circumstances, including aortic arch atherosclerosis, arterial dissection, patent foramen ovale, hyperhomocysteinemia, hypercoagulable states, antiphospholipid antibody syndrome, sickle cell disease, cerebral venous sinus thrombosis, and pregnancy. Special sections address use of antithrombotic and anticoagulation therapy after an intracranial hemorrhage and implementation of guidelines.

Night blood pressure responses to atenolol and hydrochlorothiazide in black and white patients with essential hypertension

BACKGROUND

Night blood pressure (BP) predicts patient outcomes. Variables associated with night BP response to antihypertensive agents have not been fully evaluated in essential hypertension.

METHODS

We sought to measure night BP responses to hydrochlorothiazide (HCTZ), atenolol (ATEN), and combined therapy using ambulatory blood pressure (ABP) monitoring in 204 black and 281 white essential hypertensive patients. Initial therapy was randomized; HCTZ and ATEN once daily doses were doubled after 3 weeks and continued for 6 more weeks with the alternate medication added for combined therapy arms. ABP was measured at baseline and after completion of each drug. Night, day, and night/day BP ratio responses (treatment - baseline) were compared in race/sex subgroups.

RESULTS

Baseline night systolic BP and diastolic BP, and night/day ratios were greater in blacks than whites (P < 0.01, all comparisons). Night BP responses to ATEN were absent and night/day ratios increased significantly in blacks (P < 0.05). At the end of combined therapy, women, blacks, and those starting with HCTZ as opposed to ATEN had significantly greater night BP responses (P < 0.01). Variables that significantly associated with ATEN response differed from those that associated with HCTZ response and those that associated with night BP response differed from those that associated with day BP response.

CONCLUSIONS

In summary, after completion of HCTZ and ATEN therapy, women, blacks, and those who started with HCTZ had greater night BP responses. Reduced night BP response and increased night/day BP ratios occured with ATEN in blacks. Given the prognostic significance of night BP, strategies for optimizing night BP antihypertensive therapy should be considered.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT00246519.

Prevalence and risk factors for hypertension and association with ethnicity in Nigeria: results from a national survey

Background

Non-communicable diseases are now a global priority. We report on the prevalence of hypertension and its risk factors, including ethnicity, in a nationally representative sample of Nigerian adults recruited to a survey of visual impairment.

Methods

A multi-stage, stratified, cluster random sample with probability proportional to size procedures was used to obtain a nationally representative sample of 13 591 subjects aged ≥ 40 years. Of these, 13 504 (99.4%) had a blood pressure measurement.

Results

The prevalence of hypertension was 44.9% [95% confidence interval (CI): 43.5–46.3%]. Increasing age, gender, urban residence and body mass index were independent risk factors (p < 0.001). The Kanuri ethnic group had the highest prevalence of hypertension (77.5%, 95% CI: 71.0–84.0%).

Conclusions

The high prevalence of hypertension in Nigeria is a cause for concern and suggests that it is inevitable that the impact of hypertension-related ill health is imminent, with the accompanying financial and societal costs to families and the state of Nigeria.

A genetic polymorphism in the CYP19A1 gene and the risk of hypertension among midlife women

OBJECTIVE

To test whether a synonymous single nucleotide polymorphism (A→G; rs700518) in the CYP19A1 gene, which encodes the enzyme aromatase, is associated with an increased risk for hypertension of midlife women.

METHODS

In a cross-sectional study, 639 midlife women were recruited. Eligible women had their blood pressure, weight and height measured, and donated a blood sample for hormone and genetic analyses. The participants also completed a detailed study survey. Women were grouped according to their genotype, blood pressure measurements, and medical history. The data were analyzed using logistic and linear regression models. The study had 80% power to detect small differences in mean systolic blood pressure (SBP; 4.5 mmHg) and diastolic blood pressure (DBP; 3 mmHg).

RESULTS

The selected polymorphism was significantly associated with hypertension and SBP in unadjusted analyses. Interestingly, women with hypertension were more likely to be homozygous for the A allele (AA) compared to women who were not categorized as having hypertension. Further, the mean SBP was significantly higher for women who were homozygous for the A allele when compared to women carrying the other genotypes (AG or GG). The unadjusted association between DBP values and genotype was of borderline statistical significance (p=0.07). However, after adjustment for potential confounders (age, race, body mass index (BMI), smoking and physical activity), the associations between genotype and hypertension/blood pressure were attenuated and not statistically significant.

CONCLUSION

The rs700518 polymorphism in the CYP19A1 is not associated with hypertension in our sample of midlife women. Other factors, including race and BMI, appear to play a greater role.

Racial disparity in blood pressure: is vitamin D a factor?

BACKGROUND

Higher prevalence of hypertension among African Americans is a key cause of racial disparity in cardiovascular morbidity and mortality. Explanations for the difference in prevalence are incomplete. Emerging data suggest that low vitamin D levels may contribute.

OBJECTIVE

To assess the contribution of vitamin D to racial disparity in blood pressure.

DESIGN

Cross-sectional analysis.

PARTICIPANTS

Adult non-Hispanic Black and White participants from the National Health and Nutrition Examination Survey 2001-2006.

MEASURES

We assessed Black-White differences in systolic blood pressure (SBP) controlling for conventional risk factors, and then additionally, for vitamin D (serum 25[OH]D).

RESULTS

The sample included 1984 and 5156 Black and White participants ages 20 years and older. The mean age-sex adjusted Black-White SBP difference was 5.2 mm Hg. This difference was reduced to 4.0 mm Hg with additional adjustment for socio-demographic characteristics, health status, health care, health behaviors, and biomarkers; adding 25(OH)D reduced the race difference by 26% (95% CI 7-46%) to 2.9 mm Hg. This effect increased to 39% (95% CI 14-65%) when those on antihypertensive medications were excluded. Supplementary analyses that controlled for cardiovascular fitness, percent body fat, physical activity monitoring, skin type and social support yielded consistent results.

CONCLUSION

In cross-sectional analyses, 25(OH)D explains one quarter of the Black-White disparity in SBP. Randomized controlled trials are required to determine whether vitamin D supplementation could reduce racial disparity in BP.

Mortalidade por raça/cor: evidências de desigualdades sociais em Vitória (ES), Brasil

OBJETIVO: Analisar a mortalidade por causa básica, sexo e raça/cor a partir do sistema de informações sobre mortalidade (SIM), em Vitória (ES), no período de 2003 a 2006. MÉTODOS: Foram calculados e analisados os coeficientes de mortalidade, segundo causa básica e sexo por raça/cor, bem como a idade média e mediana de óbito por causa básica, sexo e raça/cor. Foi calculado o risco relativo (RR) por sexo, idade e causa básica (p<0,05 e IC 95%). RESULTADOS: A completitude da variável raça/cor no SIM variou de 1% em 1996 para 81% em 2006. Foi observado maior RR de óbito entre negros para transtornos mentais e comportamentais (RR=9,29), causas mal definidas (RR=8,71) e causas externas (RR=5,71). Entre mulheres negras, as causas externas apresentaram maior RR (2,38). Foi encontrada uma variação de até 33 anos na idade mediana do óbito entre brancos e negros. Conclusão: Este estudo reitera a existência de desigualdades raciais/étnicas na mortalidade, destacando-se a mortalidade por transtornos mentais e causas externas, além da mortalidade precoce que ocorre na população negra.

Effect of beta blockers on central aortic pressure in African-Americans

The objective of this study was to evaluate the vascular effects of heart rate (HR) reduction with BB therapy in African Americans (AA). Beta-blockers (BB) offer less cardiovascular protection than other hypertensive drugs. Studies of Caucasian subjects suggest this may be due to an adverse effect of HR lowering on arterial wave reflection. We studied 506 subjects (age 63 ± 14 years, 52% were treated with BB). Central systolic (C-SBP) and pulse pressure (C-PP), augmented pressure (AP), and augmentation index (AI) were obtained via applanation tonometry (Sphygmocor). On univariate analysis, HR correlated inversely with BB use, C-SBP, AP, and AI (all P < .001), but not P-SBP. Multivariate analysis showed P-SBP and HR to be major determinants of C-SBP (R(2) = 0.95). Generalized linear model analysis showed higher C-SBP (P < .05) and C-PP (P = .04), but similar P-SBP (P = .24) in the BB group. After HR adjustment, differences in C-SBP, C-PP, AI, and AP were attenuated, suggesting HR to be a determinant of C-SBP. BB use is associated with higher C-SBP and lower PPA in hypertensive AA despite similar P-SBP. C-SBP is HR-dependent. HR reduction with BB accounts for less effective central blood pressure control in AA, similar to that reported in Caucasians.

Weight status and high blood pressure among low-income African American men

Obesity is a biological risk factor or comorbidity that has not received much attention from scientists studying hypertension among African American men. The purpose of this study was to examine the relationship between weight status and high blood pressure among African American men with few economic resources. The authors used surveillance data collected from low-income adults attending community- and faith-based primary care clinics in West Tennessee to estimate pooled and group-specific regression models of high blood pressure. The results from group-specific logistic regression models indicate that the factors associated with hypertension varied considerably by weight status. This study provides a glimpse into the complex relationship between weight status and high blood pressure status among African American men. Additional research is needed to identify mechanisms through which excess weight affects the development and progression of high blood pressure.

Guidelines for the prevention of stroke in patients with stroke or transient ischemic attack: a guideline for healthcare professionals from the american heart association/american stroke association

The aim of this updated statement is to provide comprehensive and timely evidence-based recommendations on the prevention of ischemic stroke among survivors of ischemic stroke or transient ischemic attack. Evidence-based recommendations are included for the control of risk factors, interventional approaches for atherosclerotic disease, antithrombotic treatments for cardioembolism, and the use of antiplatelet agents for noncardioembolic stroke. Further recommendations are provided for the prevention of recurrent stroke in a variety of other specific circumstances, including arterial dissections; patent foramen ovale; hyperhomocysteinemia; hypercoagulable states; sickle cell disease; cerebral venous sinus thrombosis; stroke among women, particularly with regard to pregnancy and the use of postmenopausal hormones; the use of anticoagulation after cerebral hemorrhage; and special approaches to the implementation of guidelines and their use in high-risk populations.

How family, community, and work structured high blood pressure accounts: from African Americans in Washington State

High blood pressure is one of the most often researched, yet least understood health disparities among African Americans. This descriptive, critical discourse analysis examined how family and community demographics and paid and unpaid work structured participants' accounts of high blood pressure experiences in Washington State. Thirty-seven urban-dwelling African American women (n = 17) and men (n = 20) in Washington State enrolled in the study from 2000-2001. Reports about stress, concerns, worry, loneliness, and paid and unpaid work were given in semi-structured interviews. Analysis results are embedded within three major themes: (a) Aware, But Not Informed, (b) Negotiating Self, Kin and Community Health, and (c) Distant Lives, Distant Love. Knowledge of life factors influencing African Americans' high blood pressure appraisals will help develop context-specific health programs focused on their concerns.

Improved attainment of blood pressure and cholesterol goals using single-pill amlodipine/atorvastatin in African Americans: the CAPABLE trial

OBJECTIVE

To investigate the efficacy and safety of single-pill amlodipine/atorvastatin therapy for the simultaneous treatment of hypertension (HTN) and dyslipidemia in African Americans.

PATIENTS AND METHODS

Conducted between July 19, 2004, and August 9, 2005, the Clinical Utility of Caduet in Simultaneously Achieving Blood Pressure and Lipid End Points trial was a 20-week, open-label, noncomparative, multicenter trial of the efficacy and safety of single-pill amlodipine/atorvastatin in controlling elevated blood pressure (BP) and low-density lipoprotein cholesterol (LDL-C) in African Americans with concomitant HTN and dyslipidemia and either no additional risk factors, 1 or more cardiovascular risk factors, or coronary heart disease or a risk equivalent. Eight dosage strengths of single-pill amlodipine/atorvastatin were flexibly titrated. The primary efficacy assessment of the main trial was the percentage of patients who attained the LDL-C treatment goals of both the Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure and the National Cholesterol Education Program Adult Treatment Panel III.

RESULTS

Of the 1170 African American patients screened, 501 were enrolled in the study and 499 received drug therapy. At end point, 236 (48.3%) of 489 patients reached both their BP and LDLC goals (vs 4 [0.8%] of 484 at baseline); 280 (56.8%) of 493 reached BP goals (vs 7 [1.4%] of 494 at baseline); and 361 (73.7%) of 490 reached LDL-C goals (vs 138 [28.5%] of 484 at baseline). Among the 499 patients receiving drug therapy, common treatment-related adverse events were peripheral edema (17 patients [3.4%]), headache (11 [2.2%]), myalgia (11 [2.2%]), and constipation (10 [2.0%]).

CONCLUSION

Single-pill amlodipine/atorvastatin therapy was well tolerated and effectively targeted HTN and dyslipidemia in this population of African Americans who were at risk of cardiovascular disease.

Understanding social disparities in hypertension prevalence, awareness, treatment, and control: the role of neighborhood context

The spatial segregation of the US population by socioeconomic position and especially race/ethnicity suggests that the social contexts or "neighborhoods" in which people live may substantially contribute to social disparities in hypertension. The Chicago Community Adult Health Study did face-to-face interviews, including direct measurement of blood pressure, with a representative probability sample of adults in Chicago. These data were used to estimate socioeconomic and racial-ethnic disparities in the prevalence, awareness, treatment, and control of hypertension, and to analyze how these disparities are related to the areas in which people live. Hypertension was significantly negatively associated with neighborhood affluence/gentrification, and adjustments for context eliminated the highly significant disparity between blacks/African-Americans and whites, and reduced the significant educational disparity by 10-15% to borderline statistical significance. Awareness of hypertension was significantly higher in more disadvantaged neighborhoods and in places with higher concentrations of blacks (and lower concentrations of Hispanics and immigrants). Adjustment for context completely eliminated blacks' greater awareness, but slightly accentuated the lesser awareness of Hispanics and the greater levels of awareness among the less educated. There was no consistent evidence of either social disparities in or contextual associations with treatment of hypertension, given awareness. Among those on medication, blacks were only 40-50% as likely as whites to have their hypertension controlled, but context played little or no role in either the level of or disparities in control of hypertension. In sum, residential contexts potentially play a large role in accounting for racial/ethnic and, to a lesser degree, socioeconomic disparities in hypertension prevalence and, in a different way, awareness, but not in treatment or control of diagnosed hypertension.

African Americans with asthma: genetic insights

It has been well established that genetic factors strongly affect susceptibility to asthma and its associated traits. It is less clear to what extent genetic variation contributes to the ethnic disparities observed for asthma morbidity and mortality. Individuals of African descent with asthma have more severe asthma, higher IgE levels, a higher degree of steroid dependency, and more severe clinical symptoms than individuals of European descent with asthma but relatively few studies have focused on this particularly vulnerable ethnic group. Similar underrepresentation exists for other minorities, including Hispanics. In this review, a summary of linkage and association studies in populations of African descent is presented, and the role of linkage disequilibrium in the dissection of a complex trait such as asthma is discussed. Consideration for the impact of population stratification in recently admixed populations (i.e., European, African) is essential in genetic association studies focusing on African ancestry groups. With the most recent update on the International HapMap Project, efficient selection of haplotype tagging single nucleotide polymorphisms (htSNPs) for African Americans has accelerated and efficiency of htSNPs chosen from one population to represent other continental groups (e.g., African) has been demonstrated. Cutting-edge approaches, such as genomewide association studies, admixture mapping, and phylogenetic analyses, offer new opportunities for dissecting the genetic basis for asthma in populations of African descent.

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.

An inquiry into medication meanings, illness, medication use, and the transformative potential of chronic illness among African Americans with hypertension

BACKGROUND

Hypertension is a chronic illness with serious economic and clinical consequences. The asymptomatic nature of this condition contributes to the challenge of persistent medication use.

OBJECTIVES

The objectives of this qualitative study were to explore perceptions of medication meanings, illness, identity, and biographical disruption among people with hypertension, and to examine how salient themes and categories relate to medication use.

METHODS

In-person interviews were conducted with 20 participants. Eligibility criteria included being 18 years or older, diagnosed with hypertension, and currently taking antihypertensive drug treatment. Interviews were tape-recorded and transcribed. Data were analyzed with grounded theory methodology using coding techniques and constant comparison.

RESULTS

All participants were African American and most were between 45 and 64 years. Key themes including perceptions of the medication being effective, lifesaving, part of life, and a reminder of the regimen were found to have a positive impact on medication use. Themes including fear of side effects, fear of dependency, forgetting to take medication, the medication being a hassle, and the experience of medication-related sexual side effects were found to be negatively related to medication use. Participants were cognizant of consequences of uncontrolled hypertension, and illness control was important to them. Biographical disruption was minimal. Taking medications and changing diet were the most significant changes in the lives of participants after being diagnosed with hypertension. Achievement of lifestyle modifications had a positive impact on identity.

CONCLUSIONS

Findings contribute to our understanding of medication use behavior and have implications for patient education and counseling.

A review of isosorbide dinitrate and hydralazine in the management of heart failure in black patients, with a focus on a new fixed-dose combination

BACKGROUND

It is estimated that 25% to 30% of patients with heart failure (HE) in the United States are black. Compared with nonblack patients, black patients have a reduced ability to produce endogenous nitric oxide, which may be associated with enhanced responsiveness to drugs that increase the delivery of nitric oxide, such as nitrates. When used with nitrates, hydralazine (HYD) acts as an antioxidant and prevents development of nitrate tolerance.

OBJECTIVE

This article reviews the clinical pharmacology of isosorbide dinitrate (ISDN) and HYD and clinical trials of their use in the treatment of HF, with a particular focus on the new fixed-dose combination for the treatment of HF in black patients.

METHODS

Articles or abstracts reporting the results of randomized, double-blind, controlled studies of ISDN and HYD in HF were identified through a search of the English-language literature indexed on MEDLINE and Current Contents/Clinical Medicine from 1966 to February 5, 2005, using the terms hydralazine, isosorbide dinitrate, nitrates, and heart failure. The reference lists of identified articles were reviewed for additional publications. Selected information provided by the manufacturer was also reviewed.

RESULTS

The combination of ISDN and HYD was studied in 3 large randomized controlled trials, the first and second Vasodilator in Heart Failure trials (V-HeFT I and V-HeFT II), which included approximately 27% black men, and the African-American Heart Failure Trial (A-HeFT), which included 100% self-identified black patients of both sexes. In V-HeFT I, which compared ISDN 40 mg QID and HYD 75 mg QID with prazosin 20 mg/d or placebo in 642 patients with mild to severe HF (New York Heart Association [NYHA] class II-III), those receiving ISDN and HYD had a 34% reduction in mortality risk compared with those receiving placebo (P < 0.038). In V HeFT II, which compared the same dosages of ISDN and HYD with enalapril 20 mg/d in 804 patients with NYHA class II-IV HF, those receiving enalapril had a 28% reduction in mortality risk compared with those receiving ISDN and HYD (P = 0.016). A predetermined subanalysis of VHeFT I and V-HeFT II found that black patients receiving ISDN and HYD had a 47% reduction in relative mortality risk compared with nonblack patients (hazard ratio = 0.53 vs 130, respectively; P = 0.04). In A-HeFT, which compared combination ISDN/HYD 40/75 mg TID with placebo in 1050 patients with moderate to severe HF (NYHA class III-IV), ISDN/HYD was associated with fewer deaths compared with placebo (32 vs 54, respectively; P = 0.02), a lower incidence of first hospitalizations for HF (85 vs 130; P = 0.002), and a larger number of patients with marked improvement (>10 units) in quality-of-life scores, as measured on the Minnesota Living with Heart Failure Questionnaire (180 vs 166; P = 0.01). In A-HeFT, adverse events occurring with a greater incidence in the ISDN/HYD group than the placebo group were headache (49.5% vs 21.1%, respectively), dizziness (30.1% vs 13.7%), nausea and vomiting (9.7% vs 6.1%), hypotension (7.9% vs 4.4%), sinus congestion (4.3% vs 1.7%), and tachycardia (4.1% vs 2.7%). A pharmacoeconomic analysis based on health care resource utilization in A-HeFT found the ISDN/HYD combination product to be cost-effective over a wide range of acquisition costs (up to 12 US dollars/d ).

CONCLUSIONS

The findings of these 3 large controlled clinical trials support the efficacy of ISDN and HYD in patients with HE Using a composite end point of mortality, HT hospitalization, and quality of life, the A-HeFT study found benefits to adding the fixed-dose ISDN/HYD combination product to standard therapy in self-identified black patients of African descent with moderate to severe HF.

The burden of hypertension: mental representations of African American women

A qualitative study using focus groups to explore African American women's mental representations of hypertension was conducted with 47 participants. The ability of participants to select and perform rational procedures for threat management also was explored. Leventhal's Self-Regulation Process Model was used to guide the development of the study. African American women (mean age 50.11 years) were recruited from community settings to participate in focus groups. Transcripts from the focus groups were coded and analyzed using comparative analysis. Four themes were generated from the women's mental representations: (1) Vulnerability and Inevitability, (2) Biobehavioral Assaults, (3) Barriers to Effective Management, and (4) Culturally Relevant Remedies. Hypertension was perceived as a significant disease threat; causality was associated with risk factors interacting within the context of psychological stress. Acquiring a clear perspective of how African American women perceive hypertension and their ability to reduce risk factors can assist in developing a model for stimulating the use of health promotive behavior.

Genetic epidemiology of health disparities in allergy and clinical immunology

The striking racial and ethnic disparities in disease prevalence for common disorders, such as allergic asthma, cannot be explained entirely by environmental, social, cultural, or economic factors, and genetic factors should not be ignored. Unfortunately, genetic studies in underserved minorities are hampered by disagreements over the biologic construct of race and logistic issues, including admixture of different races and ethnicities. Current observations suggest that the frequency of high-risk variants in candidate genes can differ between African Americans, Puerto Ricans, and Mexican Americans, and this might contribute to the differences in disease prevalence. Maintenance of certain allelic variants in the population over time might reflect selective pressures in previous generations. For example, significant associations between markers in certain candidate genes (eg, STAT6, ADRB2, and IFNGR1) for traits such as high total IgE levels observed in resistance to extracellular parasitic disease in one population and atopic asthma in another supports the common disease/common variant model for disease. Herein is a discussion of how genetic variants might explain, at least in part, the marked disparities observed in risk to allergic asthma.

Illuminating cancer health disparities using ethnogenetic layering (EL) and phenotype segregation network analysis (PSNA)

BACKGROUND

Resolving cancer health disparities continues to befuddle simplistic racial models. The racial groups alluded to in biomedicine, public health, and epidemiology are often profoundly substructured.

METHODS

EL and PSNA are computational assisted techniques that focus on microethnic group (MEG) substructure.

RESULTS

Geographical variations in cancer may be due to differences in MEG ancestry or similar environmental exposures to a recognized carcinogen. Examples include breast and prostate cancers in the Chesapeake Bay region and Bight of Biafra biological ancestry, hypertension and stroke in the Carolina Coast region and Central African biological ancestry, and pancreatic cancer in the Mississippi Delta region and dietary/medicinal exposure to safrol from Sassafras albidum.

Genetic determinants and ethnic disparities in sepsis-associated acute lung injury

Acute lung injury (ALI) is a common and devastating illness that occurs in the context of sepsis and other systemic inflammatory disorders. In systemic illnesses like sepsis, only a subset of patients develops ALI even when pathologic stimuli are apparently equivalent, suggesting that there are genetic features that may influence its onset. Considerable obstacles in defining the exact nature of the pathogenesis of ALI include substantial phenotypic variance, incomplete penetrance, complex gene-environment interactions and a strong potential for locus heterogeneity. Moreover, ALI arises in a critically ill population with diverse precipitating factors and appropriate controls that best match the reference population have not been agreed upon. The sporadic nature of ALI precludes conventional approaches such as linkage mapping for the elucidation of candidate genes, but tremendous progress has been made in combining robust, genomic tools such as high-throughput, expression profiling with case-control association studies in well characterized populations. Similar to trends observed in common, complex traits such as hypertension and diabetes, some of these studies have highlighted differences in allelic variant frequencies between European American and African American ALI patients for novel genes which may explain, in part, the complex interplay between ethnicity, sepsis and the development of ALI. In trying to understand the basis for contemporary differences in allelic frequency, which may lead to differences in susceptibility, the potential role of positive selection for genetic variants in ancestral populations is considered.