Perspective on selected issues in cardiovascular disease research with a focus on black Americans

Cardiovascular disease incidence among females in South Carolina by type of oral contraceptives, 2000-2013: a retrospective cohort study

INTRODUCTION

Certain types of oral contraceptives can produce favorable effects on lipid metabolism and vascular tone, while others have potentially detrimental effects. Endogenous and exogenous hormones exert different effects on high-density lipoprotein (HDL) and low-density lipoprotein (LDL) depending on the type, combination, and dose of the hormone. The estrogenic and progestogenic effects of exogenous hormones on HDL and LDL are inconsistent. Studying surrogate end points (LDL, HDL levels) may provide a misleading picture of OCs.

METHODS

Medicaid data from 2000 to 2013 were used to assess the relationship between the type of OCs and CVD incidence. Multivariable logistic regression was used to model relationships between cardiovascular disease and OC use adjusting for potential confounders.

RESULTS

Compared to combined oral contraceptives (COC), progestin-only oral contraceptives (POC) were associated with decreased heart disease and stroke incidence after adjusting for important covariates (OR 0.74; 95 % CI 0.57, 0.97 and OR 0.39; 95 % CI 0.16, 0.95, respectively). However, there was a positive association between POC + COC and both heart disease and stroke incidence (OR 2.28; 95 % CI 1.92, 2.70 and OR 2.12; 95 % CI 1.34, 3.35, respectively).

CONCLUSION

In light of an association between POC use and decreased heart disease and stroke, women's CVD risk factors should be carefully considered when choosing which OC to use. Baseline CVD risk should be a part of the discussion between women and their primary care providers when making choices regarding OCs.

Association of micro albuminuria with diastolic function in obese normotensive no diabetic individuals

Background:

Recently, an association between impaired diastolic function and increased urinary albumin excretion has been hypothesized.

Objectives:

We tried to assess the association between diastolic function and micro albuminuria in normotensive no diabetic obese individuals.

Patients and Methods:

This cross-sectional study was conducted on 186 consecutive obese normotensive no diabetic individuals who were older than 18 years and attended the outpatient health clinic at the Tehran Municipality in 2011. Systolic and diastolic blood pressures were measured using a standard mercury sphygmomanometer. Micro albuminuria was defined as abnormal urinary albumin to creatinine ratio (UACR) between 30 and 300 mg/g/d.

Results:

An adverse significant linear correlations was found between the UACR measurement and diastolic function (r = -0.184 and P = 0.012); however, this correlation was insignificant for systolic function (r = 0.007 and P = 0.926). Multivariable linear regression analysis showed that UACR index had a significant reverse correlation with diastolic function (Standardized Beta = -0.218 and P = 0.006).

Conclusions:

Our study obtained some evidences on the association of micro albuminuria with diastolic dysfunction in obese normotensive no diabetic individuals. Nonetheless, more assessment is necessary for obtaining a causal relationship between micro albuminuria and diastolic dysfunction.

Hypertension in minority populations: new guidelines and emerging concepts

Persistent disparities in hypertension, CKD, and associated cardiovascular disease have been noted in the United States among racial/ethnic minority groups. Overall, these disparities are largely mediated by social determinants of health. Yet, emerging data suggest additional biologic factors in racial/ethnic disparities in hypertension prevalence, complications, particularly CKD, and responses to treatment. Nevertheless, race is a social construct and not a physiologic concept, and ethnicity, federally defined as the binary "Hispanic/Latino" or "not Hispanic/Latino," is also imprecise. However, race/ethnicity categories may help interpret health-related data, including surveillance and research, and are important in ensuring that clinical trials remain generalizable to diverse populations. There is significant heterogeneity among prespecified groups and, perhaps, greater genetic differences within than between certain racial/ethnic groups. This review will explore hypertension epidemiology, pathophysiology, and management among the diverse and growing US minority groups, specifically African Americans and Hispanics because much less data are available across the wide spectrum of diverse populations. We will highlight the intersection of hypertension and increasingly prevalent CKD, particularly in African Americans. Finally, we propose multidimensional treatment approaches to hypertension among diverse populations, encompassing population, community, health system, and individual-based approaches.

Psychometric properties of the Cook Medley hostility scale and its association with inflammatory markers in African Americans

Dispositional hostility as measured by the Cook Medley Hostility (Ho) Scale has been associated with inflammation and cardiovascular disease (CVD) risk. There is evidence that suggests that factors of hostility are more useful in predicting poor cardiovascular health outcomes than a single hostility construct. The purpose of this study was to investigate the latent factors of hostility and their association with inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP) in an African-American community sample. This racial/ethnic group has been largely excluded from this line of research despite their disproportionate burden of CVD and its risk factors. Blood samples for plasma IL-6 and CRP were collected on the same day the Ho Scale was administered. Plasma IL-6 and CRP levels were determined using enzymatic-linked immunosorbent assay. Confirmatory factor analysis revealed three latent main factors of hostility: Neuroticism, Manichaeism and Moral Primitiveness, and seven intermediary subfactors. Of the subfactors, hostile affect was significantly associated with greater CRP levels and predatory self interest was significantly associated with greater IL-6 levels. Findings suggest that African Americans have a unique pattern of hostility and two latent subfactors are associated with a marker of CVD. Based on the findings, future studies should aim to further delineate how hostility influences health outcomes in African Americans.

Evidence to support church-based health promotion programmes for African Canadians at risk for cardiovascular disease

High quality management of cardiovascular disease is a critical health issue for people of African descent as this group is more likely than the general population to have greater coexisting cardiovascular comorbidities. The higher than average rates of cardiovascular conditions among Black populations are a cause for concern. In an effort to combat the disproportionate number of African Americans experiencing cardiovascular conditions a significant number of churches within the African American community have initiated health promotion programmes and/or services. Health organisations and agencies in the United States are keen to support and encourage these programmes for cardiovascular disease risk populations (i.e. African Americans and other minority groups, such as the Hispanic community). Indeed these health organisations and agencies recognise the need to promote healthier habits among African Americans and other minority groups as statistics continue to show health disparities among these populations within the US health care system. This paper attempts to encourage Canadian health agencies, organizations and practitioners to support similar CBHPPs initiatives for the African Canadian population. The historical significance of the church in Black Canadian communities is also examined.

Postprandial endothelial function does not differ in women by race: an insulin resistance paradox?

Insulin resistance is associated with endothelial dysfunction. Because African-American women are more insulin-resistant than white women, it is assumed that African-American women have impaired endothelial function. However, racial differences in postprandial endothelial function have not been examined. In this study, we test the hypothesis that African-American women have impaired postprandial endothelial function compared with white women. Postprandial endothelial function following a breakfast (20% protein, 40% fat, and 40% carbohydrate) was evaluated in 36 (18 African-American women, 18 white women) age- and body mass index (BMI)-matched (age: 37 ± 11 yr; BMI: 30 ± 6 kg/m(2)) women. Endothelial function, defined by percent change in brachial artery flow-mediated dilation (FMD), was measured at 0, 2, 4, and 6 h following a meal. There were no significant differences between the groups in baseline FMD, total body fat, abdominal visceral fat, and fasting levels of glucose, insulin, total cholesterol, low-density lipoprotein cholesterol, or serum estradiol. Although African-American women were less insulin-sensitive [insulin sensitivity index (mean ± SD): 3.6 ± 1.5 vs. 5.2 ± 2.6, P = 0.02], both fasting triglyceride (TG: 56 ± 37 vs. 97 ± 49 mg/dl, P = 0.007) and incremental TG area under the curve (AUC(0-6hr): 279 ± 190 vs. 492 ± 255 mg·dl(-1)·min(-1)·10(-2), P = 0.008) were lower in African-American than white women. Breakfast was associated with a significant increase in FMD in whites and African-Americans, and there was no significant difference in postprandial FMD between the groups (P > 0.1 for group × time interactions). Despite being insulin-resistant, postprandial endothelial function in African-American women was comparable to white women. These results imply that insulin sensitivity may not be an important determinant of racial differences in endothelial function.

High Sensitivity C - Reactive Protein is Associated with Diastolic Dysfunction in Young African Americans without Clinically Evident Cardiac Disease

Background:

Diastolic dysfunction (DD) is associated with myocardial fibrosis mediated by inflammation. Higher levels of inflammation found in African Americans (AAs) may predict DD among asymptomatic individuals. We tested the hypothesis that high sensitivity C-reactive protein (hs-CRP), a biomarker of inflammation, is associated with DD in asymptomatic AAs.

Methods:

We prospectively recruited 107 asymptomatic AAs without any history of cardiac, renal or inflammatory diseases or alcoholism. We measured hs-CRP and B-type Natriuretic peptide (BNP) levels and estimated left ventricular end diastolic pressure (LVEDP), mass and systolic function with echocardiography. Multivariate logistic regression analysis was used to define whether hs-CRP is an independent predictor of LVEDP.

Results:

Among 107 subjects: the mean age was 48±10 yrs, 58 (54%) were men, 59 (55%) had diabetes (DM), 48 (45%) had hypertension (HTN), the mean BMI was 30.5±4.8 and the mean ejection fraction was 63.1±5.8%. DD was present in 56(52%) subjects, 38 (36%) of whom also had a high LVEDP. On multivariate analysis, hs-CRP was independently associated with DD [odds ratio 3.36 (95% CI= 1.07 - 10.5, p = 0.04]. There was a 61% and 133% increase in the prevalence of any DD and DD with high LVEDP, respectively, between the lowest and the highest hs-CRP quartiles.

Conclusion:

Diastolic dysfunction is prevalent among asymptomatic African Americans and it is independently associated with elevated level of hs-CRP, an inflammation marker.

Blood pressure variability is significantly associated with ECG left ventricular mass in normotensive Africans: the SABPA Study

The prognostic significance of blood pressure (BP) variability has lately enjoyed considerable attention. The need for early markers of cardiovascular dysfunction is imperative in black South Africans who have a significant risk for cardiovascular disease. We therefore compared 24-h BP variability with various traditional and advanced BP measurements, regarding their association with sub-clinical organ damage in black and white South Africans. The study included 409 African and Caucasian teachers aged 25-60 yrs. We measured office BP, 1-min continuous (finger) BP, ambulatory BP, BP reactivity and determined weighted 24-h BP variability. Albumin-to-creatinine ratio, Cornell product and carotid cross-sectional wall area (CSWA) were measures of organ damage. Africans had higher 24-h BP, BP variability, BP reactivity and sub-clinical organ damage (P<0.001). Correlations of BP variability with organ damage were overall weak when compared with other BP measurements. In normotensive groups, we found an independent association of 24-h systolic BP (SBP) variability with Cornell product only in Africans (r=0.37; P=0.01), confirmed in multiple regression models, with 24-h SBP included in the model. Only in hypertensive Caucasians, a significant correlation between CSWA and 24-h SBP variability was evident (r=0.30; P=0.01), although CSWA indicated stronger correlations with office or 24-h SBP than 24-h SBP variability. To conclude, 24-h SBP variability could potentially be an effective measure for the early detection of normotensive Africans at increased risk for the development of cardiovascular complications. Its usefulness based on associations with target organ damage in hypertensive groups seems to be less than traditional office or 24-h BP measurements.

Ethnic differences in triglyceride levels and high-density lipoprotein lead to underdiagnosis of the metabolic syndrome in black children and adults

The metabolic syndrome was designed to identify individuals at high risk for the development of type 2 diabetes and cardiovascular disease. Compared with whites, blacks have higher rates of diabetes and cardiovascular disease. Paradoxically, blacks have a lower prevalence of the metabolic syndrome. According to the criteria set by National Cholesterol Education Treatment Program-Adult Treatment Panel III, to diagnose the metabolic syndrome, 3 of 5 characteristics must be present. These characteristics are low high-density lipoprotein levels, increased triglyceride levels, central obesity, hypertension, and fasting hyperglycemia. Examining each of these factors individually, blacks are more likely than whites to have obesity, hypertension, and diabetes. In contrast, blacks are less likely than whites to have either elevated triglyceride or low high-density lipoprotein levels. Ethnic differences in lipid levels may largely explain why blacks have a lower than expected prevalence of the metabolic syndrome. In this review we will describe in children and adults ethnic differences in the epidemiologic study of conditions associated with the metabolic syndrome, as well as focus on each of the parameters of the metabolic syndrome. Overall, we conclude that an ethnic-specific formulation of the lipid criteria in the metabolic syndrome may lead to better identification of blacks at high risk for development of diabetes and cardiovascular disease.

Incidental renal artery calcifications: a study of 350 consecutive abdominal computed tomography scans

BACKGROUND

Calcifications in arteries are thought to represent atherosclerosis.

METHODS

Consecutive abdominal tomographic scans performed during a 4-month period were evaluated and assessed for renal artery calcifications (RAC). Scans that showed calcifications were evaluated for renal artery narrowing and for various characteristics of the atherosclerotic plaque.

RESULTS

Of 350 consecutive examinees, 43% were men, 40% had hypertension and 38% had hypercholesterolaemia. The age was 61 +/- 13 years. Aortic calcifications were found in 54% and RAC in 102 (29%), of whom 53 had bilateral calcifications. Subjects with RAC were older, 72 +/- 6 versus 55 +/- 12 years. Adjusted odds ratios of RAC were 2.2 (95% CI 1.1-4.6) for male gender, 2.4 (1.2-4.8) for hypertension and 2.9 (1.4-5.8) for hypercholesterolaemia, whereas family history of hypertension was protective with 0.5 (0.3-0.9). All patients with calcified renal arteries had aortic calcifications, versus 35% of those without RAC. A significant correlation was found between the severity of calcifications and the degree of renal artery narrowing (r = 0.7), and also between the presence of bilateral calcifications and a high-grade narrowing.

CONCLUSIONS

RAC strongly relates to atherosclerosis. Calcifications and artery narrowing may have a role in the pathogenesis of hypertension. Bilateral calcifications suggest atherosclerotic renal artery stenosis.

Factors associated with weight loss after gastric bypass

BACKGROUND

Gastric bypass (GBP) is the most common operation performed in the United States for morbid obesity. However, weight loss is poor in 10% to 15% of patients. We sought to determine the independent factors associated with poor weight loss after GBP.

DESIGN

Prospective cohort study. We examined demographic, operative, and follow-up data by means of multivariate analysis. Variables investigated were age, sex, race, marital and insurance status, initial weight and body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared), comorbidities (diabetes mellitus, hypertension, joint disease, sleep apnea, hyperlipidemia, and psychiatric disease), laparoscopic vs open surgery, gastric pouch area, gastrojejunostomy technique, and alimentary limb length.

SETTING

University tertiary referral center.

PATIENTS

All patients at our institution who underwent GBP from January 1, 2003, through July 30, 2006.

MAIN OUTCOME MEASURES

Weight loss at 12 months defined as poor (< or =40% excess weight loss) or good (>40% excess weight loss).

RESULTS

Follow-up data at 12 months were available for 310 of the 361 patients (85.9%) undergoing GBP during the study period. Mean preoperative BMI was 52 (range, 36-108). Mean BMI and excess weight loss at follow-up were 34 (range, 17-74) and 60% (range, 8%-117%), respectively. Thirty-eight patients (12.3%) had poor weight loss. Of the 4 variables associated with poor weight loss in the univariate analysis (greater initial weight, diabetes, open approach, and larger pouch size), only diabetes (odds ratio, 3.09; 95% confidence interval, 1.35-7.09 [P = .007]) and larger pouch size (odds ratio, 2.77;95% confidence interval, 1.81-4.22 [P <.001]) remained after the multivariate analysis.

CONCLUSIONS

Gastric bypass results in substantial weight loss in most patients. Diabetes and larger pouch size are independently associated with poor weight loss after GBP.

Relationship between Aortic Atherosclerosis and Dental Loss in an Inner-City Population

Prior studies have suggested an association between atherosclerosis and periodontal disease, both of which are more prevalent in certain minority and economically disadvantaged groups. Few studies have addressed the relationship between cardiovascular disease and dentition among ethnically diverse populations. We studied 131 subjects (60% females, age 59 ± 15 years) who were referred for clinically indicated transesophageal echocardiography. Dental loss was more severe in patients with hypertension ( P < .001), diabetes ( P = .05), coronary artery disease ( P = .04), and calcium channel blocker use ( P = .04). On univariate analysis, maximal aortic intima—media thickness (MAIMT) was significantly correlated with dental loss ( r = .40; P < .001). Age was correlated with MAIMT ( R = .41; P < .001) and with dental loss ( r = .57; P < .001). On multivariate analysis, dental loss ( P = .03) and history of coronary artery disease ( P = .04) were independent predictors of MAIMT ( R 2 = .44). In this inner-city predominantly African American population, atherosclerosis and dental loss are age dependent and are interrelated independent of age.

Effectiveness of ezetimibe added to ongoing statin therapy in modifying lipid profiles and low-density lipoprotein cholesterol goal attainment in patients of different races and ethnicities: a substudy of the Ezetimibe add-on to statin for effectiveness trial

OBJECTIVE

To examine whether the improvements in lipid profiles and low-density lipoprotein cholesterol (LDL-C) goal attainment found in the Ezetimibe Add-On to Statin for Effectiveness trial occurred equally in the black, Hispanic, and white patient populations enrolled in the study.

PATIENTS AND METHODS

In this double-blind, placebo-controlled study, patients were recruited from 299 community-based practices across the United States (January to August 2003). Patients with, hypercholesterolemia and LDL-C levels exceeding National Cholesterol Education Program Adult Treatment Panel III goals were randomized (2:1) to receive either ezetimibe (10 mg/d) or placebo in addition to their ongoing statin therapy for 6 weeks.

RESULTS

A total of 5802 patients were screened at baseline for the Ezetimibe Add-On to Statin for Effectiveness study. Of these, 2772 were excluded, and the remaining 3030 eligible patients were randomized. Ezetimibe, compared with placebo, added to statin therapy significantly reduced LDL-C levels from statin-treated baseline by 23.0% (white patients), 23.0% (black patients), and 21.0% (Hispanic patients). This effect was consistent across race and ethnicity groups (P > .50 for treatment-by-race interactions). Ezetimibe added to statin therapy also statistically significantly (P < .001) increased the percentage of patients attaining their LDL-C goal for their National Cholesterol Education Program Adult Treatment Panel III risk category in black (63.0%), Hispanic (64.8%), and white (72.3%) patients compared with placebo plus statin (32.9% black patients, 19.0% Hispanic patients, and 19.7% white patients). Ezetimibe treatment improved other lipid parameters across groups, including triglyceride, high-density lipoprotein cholesterol, non-high-density ilpoprotein cholesterol, and total cholesterol levels. Finally, the addition of ezetimibe reduced high-sensitivity C-reactive protein levels overall, and no significant interaction of treatment by race occurred (P = .83), Indicating a consistent effect across races. Ezetimibe was generally well tolerated, and no detectable differences occurred in the adverse event profile by race or ethnicity.

CONCLUSION

Ezetimibe added to statin therapy is effective and well tolerated for improving the lipid profile and LDL-C goal attainment of patients regardless of race or ethnicity.

Assessment of no-reflow regions using cardiac MRI

Ischemic myocardial injury can be broadly characterized as either reversible or irreversible. Within irreversibly injured (infarcted) regions microvascular perfusion can vary from nearly normal to nearly zero, even in the presence of an open infarct-related artery ('no-reflow'). Historically, non-invasive assessment of heterogeneous microvascular perfusion within myocardial infarcts has been problematic. More recently, however, contrast-enhanced MRI has emerged as a promising approach to the examination of these regions in patients with myocardial infarction. In this review we highlight a number of important animal and human studies of no-reflow regions examined using contrast-enhanced MRI. These studies provide evidence that contrast- enhanced MRI can accurately characterize the presence and spatial extent of no-reflow regions, discriminate between areas of necrosis with and without no-reflow, and provide clinically meaningful predictive information regarding left ventricular remodeling and patient outcome.

Hypertension artérielle du sujet noir

Hypertension is more frequent and more severe in blacks than in other racial groups. Salt-sensitive and low-renin hypertension are both more frequent in blacks. Cardiovascular morbidity appears to be similar in blacks and whites and depends on the classic cardiovascular risk factors. Kidney damage leading to end-stage renal disease is more frequent in blacks. Reduced salt intake improves drug efficacy. Diuretics and calcium channel blockers are more effective in lowering blood pressure, while angiotensin-converting-enzyme inhibitors may be more effective in preventing organ damage. Specific trials are needed to evaluate therapeutic benefits in blacks.

Issues in minority health: atherosclerosis and coronary heart disease in African Americans

Cardiovascular disease (in particular, CHD) is the leading cause of death in the United States for Americans of both sexes and of all racial and ethnic backgrounds. African Americans have the highest overall CHD mortality rate and the highest out-of-hospital coronary death rate of any ethnic group in the United States, particularly at younger ages. Contributors to the earlier onset of CHD and excess CHD deaths among African Americans include a high prevalence of coronary risk factors, patient delays in seeking medical care, and disparities in health care. The clinical spectrum of acute and chronic CHD in African Americans is the same as in whites; however, African Americans have a higher risk of sudden cardiac death and present clinically more often with unstable angina and non-ST-segment elevation myocardial infarction than whites. Although generally not difficult, the accurate diagnosis and risk assessment for CHD in African Americans may at times present special challenges. The high prevalence of hypertension and type 2 diabetes mellitus may contribute to discordance between symptomatology and the severity of coronary artery disease, and some noninvasive tests appear to have a lower predictive value for disease. The high prevalence of modifiable risk factors provides great opportunities for the prevention of CHD in African Americans. Patients at high risk should be targeted for intensive risk reduction measures, early recognition/diagnosis of ischemic syndromes, and appropriate referral for coronary interventions and cardiac surgical procedures. African Americans who have ACSs receive less aggressive treatment than their white counterparts but they should not. Use of evidence-based therapies for management of patients who have ACSs and better understanding of various available treatment strategies are of utmost importance. Reducing and ultimately eliminating disparities in cardiovascular care and outcomes require comprehensive programs of education and advocacy(Box 4) with the goals of (1) increasing provider and public awareness of the disparities in treatment; (2) decreasing patient delays in seeking medical care for acute myocardial infarction and other cardiac disorders; (3) more timely and appropriate therapy for ACSs; (4) improved access to preventive, diagnostic, and interventional cardiovascular therapies; (5) more effective implementation of evidence-based treatment guidelines; and (6) improved physician-patient communications.

Race and gender differences in C-reactive protein levels

OBJECTIVES

This study sought to determine whether there are race and gender differences in the distribution of C-reactive protein (CRP) levels.

BACKGROUND

Few data are available comparing CRP distributions in different race and gender groups. Recent clinical practice recommendations for CRP testing for cardiovascular risk assessment suggest a uniform threshold to define high relative risk (>3 mg/l).

METHODS

We measured CRP in 2,749 white and black subjects ages 30 to 65 participating in the Dallas Heart Study, a multiethnic, population-based, probability sample, and compared levels of CRP between different race and gender groups.

RESULTS

Black subjects had higher CRP levels than white subjects (median, 3.0 vs. 2.3 mg/l; p < 0.001) and women had higher CRP levels than men (median, 3.3 vs. 1.8 mg/l; p < 0.001). The sample-weight adjusted proportion of subjects with CRP levels >3 mg/l was 31%, 40%, 51%, and 58% in white men, black men, white women, and black women, respectively (p < 0.05 for each group vs. white men). After adjustment for traditional cardiovascular risk factors, estrogen and statin use, and body mass index, a CRP level >3 mg/l remained more common in white women (odds ratio [OR] 1.6; 95% confidence interval [CI] 1.1 to 2.5) and black women (OR 1.7; 95% CI 1.2 to 2.6) but not in black men (OR, 1.3; 95% CI, 0.8 to 1.9) when compared with white men.

CONCLUSIONS

Significant race and gender differences exist in the population distribution of CRP. Further research is needed to determine whether race and gender differences in CRP levels contribute to differences in cardiovascular outcomes, and whether thresholds for cardiovascular risk assessment should be adjusted for different race and gender groups.