Individual and area-level socioeconomic correlates of hypertension prevalence, awareness, treatment, and control in uMgungundlovu, KwaZulu-Natal, South Africa.

BACKGROUND: Hypertension is the second leading risk factor for death in South Africa, and rates have steadily increased since the end of Apartheid. Research on the determinants of hypertension in South Africa has received considerable attention due to South Africa's rapid urbanization and epidemiological transition. However, scant work has been conducted to investigate how various segments of the Black South African population experience this transition. Identifying the correlates of hypertension in this population is critical to the development of policies and targeted interventions to strengthen equitable public health efforts. METHODS: This analysis explores the relationship between individual and area-level socioeconomic status and hypertension prevalence, awareness, treatment, and control within a sample of 7,303 Black South Africans in three municipalities of the uMgungundlovu district in KwaZulu-Natal province: the Msunduzi, uMshwathi, and Mkhambathini. Cross-sectional data were collected on participants from February 2017 to February 2018. Individual-level socioeconomic status was measured by employment status and educational attainment. Ward-level area deprivation was operationalized by the most recent (2011 and 2001) South African Multidimensional Poverty Index scores. Covariates included age, sex, BMI, and diabetes diagnosis. RESULTS: The prevalence of hypertension in the sample was 44.4% (n = 3,240). Of those, 2,324 were aware of their diagnosis, 1,928 were receiving treatment, and 1,051 had their hypertension controlled. Educational attainment was negatively associated with hypertension prevalence and positively associated with its control. Employment status was negatively associated with hypertension control. Black South Africans living in more deprived wards had higher odds of being hypertensive and lower odds of having their hypertension controlled. Those residing in wards that became more deprived from 2001 to 2011 had higher odds of being aware of their hypertension, yet lower odds of receiving treatment for it. CONCLUSIONS: Results from this study can assist policymakers and practitioners in identifying groups within the Black South African population that should be prioritized for public health interventions. Black South Africans who have and continue to face barriers to care, including those with low educational attainment or living in deprived wards had worse hypertension outcomes. Potential interventions include community-based programs that deliver medication to households, workplaces, or community centers.

Underweight, overweight and obesity among South African adolescents: results of the 2002 National Youth Risk Behaviour Survey.

OBJECTIVE: The present paper reports the prevalence of underweight, overweight and obesity by gender, ethnicity and grade, among participants in a 2002 national survey among South African school-going youth that included height and weight measurements. DESIGN: A stratified two-stage sample was used. Nationally representative rates of underweight, overweight and obesity were calculated using weighted survey data and compared using chi2 analysis. SETTING: In all, 9224 grade 8 to grade 11 students, present at school in selected classes within selected South African government-funded schools in all nine provinces, participated in this study. Most of the students were between 13 and 19 years of age. RESULTS: Higher rates of underweight were observed for males than females as well as for black and 'coloured' than white students. Within each gender group, black and 'coloured' students had significantly higher rates of underweight than their white counterparts. Higher percentages of females than males were overweight and obese, overall and among black students. Furthermore, white male students had significantly higher rates of overweight than their black and 'coloured' counterparts. Among females, black and white students had significantly higher rates than 'coloured' students. Students in higher grades showed significantly lower rates of underweight and higher rates of overweight. DISCUSSION: These data confirm that South Africa, a developing nation in socio-economic transition, is experiencing both undernutrition and overnutrition. However, these problems are disproportionately distributed by gender, socio-economics and ethnicity. Continued surveillance of nutritional status may be one important component of a national strategy to prevent and control malnutrition.

The Burden of Cardiovascular Disease in Sub-Saharan Africa

"The burden of cardiovascular disease (CVD) in Africa is growing and changing in nature. From the predominance of rheumatic heart disease and cardiomyopathies 50 years ago to hypertensive heart disease and haemorrhagic stroke in the past 25 years. Albeit at low prevalence; an increase in incidence of ischaemic heart disease is now being seen; particularly in urban areas. These changes in the extent and nature of CVD are thought to be the result of the so-called ""epidemiological transition"". The challenge for health promotion and prevention is to accelerate the course of that transition and blunt its magnitude in order to avoid the massive epidemics of CVD that were seen in Europe and the USA in the mid-twentieth century."

Beta-blockers for hypertension.

BACKGROUND: Two recent systematic reviews found first-line beta-blockers to be less effective in reducing the incidence of stroke and the combined endpoint of stroke, myocardial infarction, and death compared to all other antihypertensive drugs taken together. However, beta-blockers might be better or worse than a specific class of drugs for a particular outcome measure so that comparing beta-blockers with all other classes taken together could be misleading. In addition, these systematic reviews did not assess the tolerability of beta-blockers relative to other antihypertensive medications. We thus undertook this review to re-assess the place of beta-blockade as first-line therapy for hypertension relative to each of the other major classes of antihypertensive drugs. OBJECTIVES: To quantify the effectiveness and safety of beta-blockers on morbidity and mortality endpoints in adults with hypertension. SEARCH STRATEGY: We searched eligible studies up to June 2006 in the Cochrane Controlled Trials Register, Medline, Embase, and reference lists of previous reviews, and by contacting hypertension experts. SELECTION CRITERIA: We selected randomised controlled trials which assessed the effectiveness of beta-blockers compared to placebo, no therapy or other drug classes, as monotherapy or first-line therapy for hypertension, on mortality and morbidity endpoints in men and non-pregnant women aged 18 years or older. DATA COLLECTION AND ANALYSIS: At least two authors independently applied study selection criteria, assessed study quality, and extracted data; with differences resolved by consensus. We expressed study results as relative risks (RR) with 95% confidence intervals (CI) and conducted quantitative analyses with trial participants in groups to which they were randomly allocated, regardless of which or how much treatment they actually received. In the absence of significant heterogeneity between studies (p>0.1), we performed meta-analysis using a fixed effects method. Otherwise, we used the random effects method and investigated the cause of heterogeneity by stratified analysis. In addition, we used the Higgins statistic (I(2)) to quantify the amount of between-study variability in effect attributable to true heterogeneity rather than chance. MAIN RESULTS: Thirteen randomised controlled trials (N=91,561 participants), which met our inclusion criteria, compared beta-blockers to placebo or no treatment (4 trials with 23,613 participants), diuretics (5 trials with 18,241 participants), calcium-channel blockers (CCBs: 4 trials with 44,825 participants), and renin-angiotensin system (RAS) inhibitors (3 trials with 10,828 participants). The risk of all-cause mortality was not different between first-line beta-blockers and placebo (RR 0.99, 95%CI 0.88 to 1.11, I(2)=0%), diuretics or RAS inhibitors, but was higher for beta-blockers compared to CCBs (RR 1.07, 95%CI 1.00 to 1.14, I(2)=2.2%; ARI=0.5%, NNH=200). The risk of total cardiovascular disease (CVD) was lower for first-line beta-blockers compared to placebo (RR 0.88, 95%CI 0.79 to 0.97, I(2)=21.4%, ARR=0.7%, NNT=140). This is primarily a reflection of the significant decrease in stroke (RR 0.80, 95%CI 0.66 to 0.96; I(2)=0%; ARR=0.5%, NNT=200); coronary heart disease (CHD) risk was not significantly different between beta-blockers and placebo. The effect of beta-blockers on CVD was significantly worse than that of CCBs (RR 1.18, 95%CI 1.08 to 1.29, I(2)=0%; ARI=1.3%, NNH=80), but was not significantly different from that of diuretics or RAS inhibitors. Increased total CVD was due to an increase in stroke compared to CCBs (RR 1.24, 95%CI 1.11 to 1.40, I(2)=0%; ARI=0.6%, NNH=180). There was also an increase in stroke with beta-blockers as compared to RAS inhibitors (RR 1.30, 95%CI 1.11 to 1.53, I(2)=29.1%; ARI=1.5%, NNH=65). CHD was not significantly different between beta-blockers and diuretics or CCBs or RAS inhibitors. In addition, patients on beta-blockers were more likely to discontinue treatment due to side effects than those on diuretics (RR 1.86, 95%CI 1.39 to 2.50, I(2)=78.2%, ARI=6.4% NNH=16) and RAS inhibitors (RR 1.41, 95%CI 1.29 to 1.54, I(2)=12.1%; ARI=5.5%, NNH=18), but there was no significant difference with CCBs. AUTHORS' CONCLUSIONS: The available evidence does not support the use of beta-blockers as first-line drugs in the treatment of hypertension. This conclusion is based on the relatively weak effect of beta-blockers to reduce stroke and the absence of an effect on coronary heart disease when compared to placebo or no treatment. More importantly, it is based on the trend towards worse outcomes in comparison with calcium-channel blockers, renin-angiotensin system inhibitors, and thiazide diuretics. Most of the evidence for these conclusions comes from trials where atenolol was the beta-blocker used (75% of beta-blocker participants in this review). However, it is not known at present whether beta-blockers have differential effects on younger and elderly patients or whether there are differences between the different sub-types of beta-blockers.

Coronary artery disease and risk factors in Black South Africans--a comparative study.

OBJECTIVE: The purpose of this study was to identify and compare coronary risk factors in different South African ethnic groups with angiographically documented significant coronary artery disease (CAD). DESIGN: An observational retrospective analysis. METHODS: Hospital records of 500 consecutive patients with no previous coronary interventions who underwent coronary angiography at Chris Hani Baragwanath Hospital, Soweto over a 2-year period were reviewed. Patients with significant CAD were selected for this study. Data analyzed included demographics, presenting diagnoses, coronary risk factors, number of coronary arteries significantly affected and extent of CAD, left ventricular ejection fraction (LVEF), and the main treatment modality for CAD. RESULTS: Of the 206 patients with significant CAD, 85 were Africans and 121 were non-Africans. There were significantly more females in the African group (31% vs 12%, P=.0023) and hypertension was more prevalent in the same group (78% vs 55%, P=.0006). Serum total (TC) and low-density lipoprotein (LDL) cholesterol were significantly lower in African than in non-African patients [189.5 (96.67-313.2) vs 228.2 (127.6-464) mg/dL; P=.0006 and 100.5 (34.8-282.3) vs 146.9 (42.54-313.2) mg/dL; P=.0001, respectively]. CONCLUSION: Cholesterol levels in this group of African patients with angiographically significant CAD are within the target range recommended by the adult treatment panel III (ATP III) guidelines of the National Cholesterol Education Program (NCEP). These data have implications for risk assessment using cholesterol and the role of cholesterol lowering treatment in populations of developing countries.

A comparative study of six commercial lipoprotein(a) assays in seventeen laboratories within the British Isles.

Seventeen laboratories in the British Isles participated in a study to compare six different commercially available immunoassays for serum lipoprotein(a) (Lp(a)) and to establish reasons for the variations in the measurement of serum Lp(a) concentrations. Pooled serum was distributed neat and after dilution at a central laboratory. In addition, the central laboratory sent unpooled serum sampled monthly from six healthy volunteers to each of the participating laboratories for 12 months. The assays all gave linear dilution curves which were parallel, although the reported values varied twofold. There were major differences in the values assigned to different manufacturers' calibrants which was not explained by whether the units employed were whole Lp(a), the protein moiety of Lp(a) or simply apolipoprotein(a). The coefficient of variation for the reported value of Lp(a) over 12 months was 33%. The component variation was 10% after adjustment for inter-laboratory and intra-laboratory variation. Some individuals clearly had a greater tendency to variable serum Lp(a) concentrations than others, but all the assays responded to this in the same way. Thus, the assays tested probably measured the same analyte. The problem of calibration could largely be addressed if agreement were reached by the manufacturers. Even with improvements in analytical precision it should be realized that multiple measurements of serum Lp(a) levels are necessary if the true mean value is to be appreciated. Individuals showing wide variation in serum Lp(a) may reward further study if its role is to be established.

A prospective study of serum lipoproteins after coronary artery bypass surgery.

We examined the acute and long-term effects of coronary artery bypass (CABG) surgery on serum lipid, lipoprotein and apolipoprotein levels. One series of 34 patients having CABG surgery was studied pre-operatively and for six weeks afterwards, and another 22 patients were investigated before and two years after CABG surgery. None of the patients studied received any lipid-lowering drug therapy or specific dietary advice. In both groups, pre-operative serum lipoprotein (a) (Lp(a)) and serum triglyceride concentrations were raised and serum high-density lipoprotein (HDL) cholesterol and apolipoprotein AI (apo AI) were low compared to healthy people. Acutely, there were profound decreases of 40-60% in the serum levels of cholesterol (p < 0.001), low-density lipoprotein cholesterol (p < 0.05), triglycerides (p < 0.01), Lp(a) (p < 0.05) and apolipoprotein B (apo B) (p < 0.05). There was a small decrease in serum apo A1 (p < 0.05), and serum HDL cholesterol showed no change. All these variables regained their pre-operative values within six weeks. Two years postoperatively, serum Lpa was 40% less than its pre-operative concentration (p < 0.001) and HDL cholesterol had increased (p < 0.001). Triglyceride levels decreased (p < 0.02) when beta-blockade was withdrawn. The long-term decrease in Lp(a) following surgery is unlikely to be due either to stopping beta-blockers or to life-style changes. Myocardial ischaemia relieved by the operation may have been partially responsible for its previously raised concentration.

Serum Lp(a) lipoprotein concentration and outcome of thrombolytic treatment for myocardial infarction.

BACKGROUND: Lp(a) lipoprotein has structural homology with plasminogen and has been shown to inhibit plasminogen activation in vitro. OBJECTIVE: To determine whether the serum concentration of Lp(a) lipoprotein present when streptokinase was given in acute myocardial infarction influenced the outcome as judged by electrocardiographic methods. PATIENTS AND DESIGN: Serum Lp(a) lipoprotein concentration was measured in 135 consecutive patients admitted with a diagnosis of acute myocardial infarction who received streptokinase treatment. Recovery from myocardial injury was assessed by the reduction in the sum of ST segment elevation measured from the J point (STJ) in the electrocardiogram immediately before streptokinase was given compared with that three hours later. RESULTS: The serum Lp(a) lipoprotein concentrations were measured within 12 hours of the onset of symptoms of myocardial infarction and were higher than in healthy reference populations. Recovery from myocardial infarction could be assessed from the STJ in 116 patients (86% of the series). Those in whom it could not had bundle branch block, left ventricular hypertrophy, did not survive three hours, or had started intravenous nitrate treatment or some other clinical procedure before or at the time the second electrocardiogram was to be recorded. Patients with reductions in STJ after streptokinase that were > 4 mm (the median decrease) had mean (range) serum Lp(a) lipoprotein concentrations of 41.0 (0.8-220) mg/dl and those with a smaller reduction in STJ had concentrations of 29.1 (1.7-151) mg/dl. The difference was not statistically significant. CONCLUSION: In this study Lp(a) lipoprotein concentration did not significantly influence the outcome of thrombolytic treatment with streptokinase.

The immediate effect of streptokinase on serum lipoprotein(a) concentration and the effect of myocardial infarction on serum lipoprotein(a), apolipoproteins A1 and B, lipids and C-reactive protein.

Lipoprotein(a) (Lp(a)) has close structural homology with plasminogen and, at least in vitro, may interfere with fibrinolysis. Any changes in the serum Lp(a) concentration during and following myocardial infarction (MI) and whether the serum Lp(a) level is affected by streptokinase (SK) are therefore of interest. Serum Lp(a) levels immediately before and 3 h after completion of an intravenous infusion of SK in 39 patients with acute MI were not significantly different (median 31.3 mg/dl before and 35.9 mg/dl after). Furthermore, SK added during the serum Lp(a) assay did not affect the result, except at very high concentrations of SK (1000 units/ml). Serum Lp(a) and fasting lipids were measured daily for 3 days following definite MI in 13 patients and then after 14 and 42 days. There was no significant change in serum Lp(a) following MI. In marked contrast, C-reactive protein levels in these patients increased steeply immediately following MI. Thus, there was no early 'acute-phase response' in serum Lp(a) levels after MI. However, greater variation in its concentration was observed at day 14 than at other times. Serum cholesterol, apolipoprotein B and apolipoprotein A1 concentrations decreased significantly following MI, whereas a significant transient increase in serum triglycerides occurred. Forty-two days after MI all lipid and lipoprotein values had regained their day 1 levels, except for apo A1, which remained depressed.