South African Hypertension Society commentary on the American College of Cardiology/American Heart Association hypertension guidelines.

In late 2017, the publication of the new American College of Cardiology (ACC)/American Heart Association (AHA) hypertension guidelines created considerable controversy. The threshold for hypertension was redefined as > 130/80 mmHg and target blood pressure < 130/80 mmHg. The purpose of this commentary is to give clarity on the position of the Southern African Hypertension Society (SAHS). In South Africa more than 90% of hypertensives are not controlled at < 140/90 mmHg. Furthermore, by redefining hypertension to a level of 130/80 mmHg, this will significantly increase the prevalence of hypertension by 43%. The new targets will necessitate greater use of health services for increased health visits to monitor patients, greater use of antihypertensives to achieve the lower target, and increased use of laboratory services to monitor for adverse effects. It is the position of SAHS that the new definition and targets are not relevant to low- and middle-income countries such as South Africa, the threshold for hypertension remains at 140/90 mmHg, and a universal target is < 140/90 mmHg for all categories of hypertension.

Why is control of hypertension in sub-Saharan Africa poor?

In sub-Saharan Africa (SSA) in 2010, hypertension (defined as systolic blood pressure ≥ 115 mmHg) was the leading cause of death, increasing 67% since 1990. It was also the sixth leading cause of disability, contributing more than 11 million adjusted life years. In SSA, stroke was the main outcome of uncontrolled hypertension. Poverty is the major underlying factor for hypertension and cardiovascular disease. This article analyses the causes of poor compliance in the treatment of hypertension in SSA and provides suggestions on the treatment of hypertension in a poverty-stricken continent.

South African hypertension practice guideline 2014.

OUTCOMES: Extensive data from many randomised, controlled trials have shown the benefit of treating hypertension (HTN). The target blood pressure (BP) for antihypertensive management is systolic < 140 mmHg and diastolic < 90 mmHg, with minimal or no drug side effects. Lower targets are no longer recommended. The reduction of BP in the elderly should be achieved gradually over one month. Co-existent cardiovascular (CV) risk factors should also be controlled. BENEFITS: Reduction in risk of stroke, cardiac failure, chronic kidney disease and coronary artery disease. RECOMMENDATIONS: Correct BP measurement procedure is described. Evaluation of cardiovascular risk factors and recommendations for antihypertensive therapy are stipulated. Lifestyle modification and patient education are cornerstones of management. The major indications, precautions and contra-indications are listed for each antihypertensive drug recommended. Drug therapy for the patient with uncomplicated HTN is either mono- or combination therapy with a low-dose diuretic, calcium channel blocker (CCB) and an ACE inhibitor (ACEI) or angiotensin receptor blocker (ARB). Combination therapy should be considered ab initio if the BP is ≥ 160/100 mmHg. In black patients, either a diuretic and/or a CCB is recommended initially because the response rate is better compared to an ACEI. In resistant hypertension, add an alpha-blocker, spironolactone, vasodilator or ß-blocker. VALIDITY: The guideline was developed by the Southern African Hypertension Society 2014©.

South African Hypertension Practice Guideline 2014 : Review Article

Outcomes : Extensive data from many randomised; controlled trials have shown the benefit of treating hypertension (HTN). The target blood pressure (BP) for antihypertensive management is systolic 140 mmHg and diastolic 90 mmHg; with minimal or no drug side effects. Lower targets are no longer recommended. The reduction of BP in the elderly should be achieved gradually over one month. Co-existent cardiovascular (CV) risk factors should also be controlled. Benefits : Reduction in risk of stroke; cardiac failure; chronic kidney disease and coronary artery disease. Recommendations : Correct BP measurement procedure is described. Evaluation of cardiovascular risk factors and recommendations for antihypertensive therapy are stipulated. Lifestyle modification and patient education are cornerstones of management. The major indications; precautions and contra-indications are listed for each antihypertensive drug recommended. Drug therapy for the patient with uncomplicated HTN is either mono- or combination therapy with a low-dose diuretic; calcium channel blocker (CCB) and an ACE inhibitor (ACEI) or angiotensin receptor blocker (ARB). Combination therapy should be considered ab initio if the BP is ? 160/100 mmHg. In black patients; either a diuretic and/or a CCB is recommended initially because the response rate is better compared to an ACEI. In resistant hypertension; add an alpha-blocker; spironolactone; vasodilator or ?-blocker

Conventional and behavioral risk factors explain differences in sub-clinical vascular disease between black and Caucasian South Africans: the SABPA study.

OBJECTIVES: There is an emerging burden of cardiovascular disease among urban black Africans in South Africa, which has been largely explained by the transition from traditional African lifestyles to more westernized behavior. We examined the role of health behaviors in explaining the excess burden of sub clinical vascular disease seen in black Africans compared to Caucasians. METHODS: This was a cross-sectional study, comprising of urban African teachers (n=192 black, 206 Caucasian) working for one of the four Kenneth Kaunda Education districts in the North West Province, South Africa. Conventional cardiovascular risk factors, 24 h ambulatory blood pressure and objectively measured physical activity (Actical® accelerometers), smoking (confirmed by serum cotinine), and alcohol (serum gamma glutamyl transferase) were assessed. The main outcome was a marker of sub-clinical vascular disease, mean carotid intima media thickness (mCIMT), measured using high resolution ultrasound. RESULTS: Compared with Caucasians, the black Africans demonstrated higher mCIMT (age and sex adjusted ß=0.044, 95% CI, 0.024-0.064 mm). The blacks also had higher 24h systolic and diastolic blood pressure, triglycerides, adiposity, and C-reactive protein. In addition, blacks were less physically active (790.0 kcal/d vs 947.3 kcal/d, p<0.001), more likely to smoke (25% vs 16.3%, p=0.002), and demonstrated higher alcohol abuse (gamma glutamyl transferase, 66.6 µ/L vs 27.2 µ/L, p<0.001) compared with Caucasians. The difference in mCIMT between blacks and Caucasians was attenuated by 34% when conventional risk factors were added to the model and a further 18% when health behaviors were included. CONCLUSION: There is an excess burden of sub clinical vascular disease seen in black Africans compared to Caucasians, which can be largely explained by health behaviors and conventional risk factors.

South African hypertension guideline 2011.

OUTCOMES: Extensive data from randomised controlled trials have shown the benefit of treating hypertension. The target blood pressure (BP) for antihypertensive management is systolic <140 mmHg and diastolic <90 mmHg with minimal or no drug side-effects; however, stricter BP control is required for patients with end-organ damage, co-existing risk factors and co-morbidity, e.g. diabetes mellitus. The reduction of BP in the elderly and in those with severe hypertension should be achieved gradually over 1 month. Co-existent risk factors should also be controlled. BENEFITS: Benefits of management include reduced risks of stroke, cardiac failure, chronic kidney disease and coronary heart disease. RECOMMENDATIONS: The correct BP measurement procedure is described, and evaluation of cardiovascular risk factors and recommendations for antihypertensive therapy are stipulated. The total cardiovascular disease risk profile should be determined for all patients to inform management strategies. Lifestyle modification and patient education are cornerstones in the management of every patient. Major indications, precautions and contra-indications to each recommended antihypertensive drug are listed. Combination therapy should be considered ab initio if the BP is ≥ 20/10 mmHg. First-line drug therapy for uncomplicated hypertension includes low-dose thiazide-like diuretics, calcium channel blockers (CCBs) or angiotensin-converting enzyme inhibitors (ACE-Is) (or ARBs - angiotensin II receptor blockers). If the target BP is not obtained, a second antihypertensive should be added from the aforementioned list. If the target BP is still not met, the third remaining antihypertensive agent should be used. In black patients either thiazide-like diuretics or CCBs can be used initially, because response rates are better than with ACE-Is or ß-blockers. In treating resistant hypertension, a centrally acting drug, vasodilator, α-blocker, spironolactone or ß-locker should be added. This guideline includes management of specific situations, i.e. hypertensive emergency and urgency, severe hypertension with target organ damage, hypertension in diabetes mellitus, resistant hypertension, fixed drug combinations, new trials in hypertension, and interactions of antihypertensive agents with other drugs. VALIDITY: The guideline was developed by the Southern African Hypertension Society.

Plasma renin responses to mental stress and carotid intima-media thickness in black Africans: the SABPA study.

The renin-angiotensin-aldosterone system can be activated by sympathetic nervous input and is thought to have an important role in the prevalence of hypertension and cardiovascular risk in black Africans. We examined (1) the association between plasma renin responses to mental stress and a marker of sub-clinical atherosclerosis; and (2) associations between resting renin and 24-h ambulatory blood pressure. Participants were 143 urbanized black African men and women (43.1 ± 7.7 years) drawn from a study of Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA). After an overnight fast, participants completed the Stroop mental stress task. Blood samples were drawn during baseline and 10 min after the task to assess the concentration of active renin in plasma. Blood pressure assessments included continuous Finometer measures during the stress testing and 24-h ambulatory monitoring. Carotid intima-media thickness (CIMT) was measured using high-resolution ultrasound. Approximately 50% of the sample responded to the task with an increase in renin concentration. Multiple linear regression analysis revealed an association between the renin stress response and CIMT (ß = 0.024, 95% confidence interval, 0.004-0.043), after adjustment for conventional risk factors, blood pressure stress responses and basal levels of renin activity (R(2) for model = 0.37). In addition, resting renin was inversely associated with ambulatory blood pressure. In summary, heightened release of renin during a laboratory mental stressor was associated with a marker of sub-clinical atherosclerosis; thus, it may be a potential mechanism in explaining the increased burden of cardiovascular disease in urbanized black Africans.

Perspectives on research in hypertension.

This is a review of my published research on hypertension over 45 years on the three main racial groups residing in KwaZulu-Natal and its main city Durban. These three groups are blacks - mainly Zulu, whites and Indians. The research focused mainly on epidemiology, determinants of the aetiology of hypertension, clinical features, varying responses to hypotensive agents among the racial groups, complications that result from hypertension and the control of hypertension.

Impact of poverty on hypertension and cardiovascular disease in sub-Saharan Africa.

Sub-Saharan Africa (SSA) has huge amounts of natural resources and a source of strategic minerals. It is not overpopulated compared to the Asian continent, yet the economic conditions have deteriorated alarmingly in recent years. It is the poorest continent and has the lowest per capita income in the world. An analysis of the causes of poverty and its impact on health, particularly cardiovascular diseases (CVD) and hypertension, was carried out and is reported on here. A 'second-wave epidemic' is currently sweeping through SSA, other developing countries and Eastern Europe, making a comprehensive CVD programme necessary. Social, economic and cultural factors impair the control of hypertension, diabetes, obesity, tobacco use and other risk factors for CVD in SSA. Primary prevention through a population-based, lifestyle-linked programme, as well as cost-effective methods for detection and management are synergistically linked. The existing healthcare infrastructure needs to be orientated to meet the challenge of CVD, while empowering the community through health education.

The limits of antihypertensive therapy--lessons from Third World to First.

A rapidly developing 'second-wave epidemic' of cardiovascular disease is flowing through developing countries and the former socialist republics. It is now evident from World Health Organisation data that coronary heart disease and cerebrovascular disease are increasing so rapidly that they will rank as numbers 1 and 5 respectively as causes of global burden of disease by the year 2020. In spite of the current low prevalence of hypertension in some countries, the total number of hypertensive subjects in the developing world is high, and a cost-analysis of possible antihypertensive drug treatment indicates that developing countries cannot afford the same treatment as developed countries. In the USA only 20% of cases of hypertension are adequately controlled (blood pressure < 140/90 mmHg), and in the developing world the figure falls to 5 - 10%. Black hypertensives have varying responses to antihypertensive therapy. They respond well to thiazide diuretics, calcium channel blockers, vasodilators such as alpha-blockers, hydrazine and reserpine, and poorly to beta-blockers, angiotensin-converting enzyme (ACE) inhibitors and angiotensin II-receptor antagonists unless these drugs are combined with a diuretic. A comprehensive cardiovascular disease (CVD) programme is necessary. There are social, economic and cultural factors that impair control of hypertension in developing countries. Hypertension control should ideally be the initial component of an integrated CVD control programme that needs to be implemented in developing countries. Primary prevention through a population-based lifestyle-linked programme, as well as cost-effective methods of detection and management, are synergistically linked. The existing health care infrastructure needs to be orientated to meet the emerging challenge of CVD, while empowering the community through health education.

Current concepts in the treatment of hypertension.

In spite of the effective drug therapy available for hypertensive patients in general, economic and social considerations continue to influence the low rate of detection, treatment and control of hypertension in the population of the developing world. The Joint National Committee on the Detection, Evaluation and Treatment of High Blood Pressure stated that in 1993 age-adjusted stroke rates rose slightly and that the age-adjusted rate of decline for coronary heart disease appeared to be levelling. Furthermore, rates for the incidence of end-stage renal disease increased, with hypertension the second most common cause. The Report also stated that hypertension control rates did not improve (National Health and Nutrition Examination Survey, NHANES III, Phase 1) from 1991 to 1994, and there were only 27% on control. These disturbing trends support the need to enhance public and professional education and to translate the results of research into improved health.

Anticardiolipin antibodies in South African patients with lupus nephritis: a clinical and renal pathological study.

AIMS: This study was conducted prospectively to ascertain the prevalence of anticardiolipin antibodies (ACAs) in patients with lupus nephritis and to determine whether this subgroup of patients differed clinically and histologically from patients without the antibody. PATIENTS AND METHODS: 40 SLE patients (26 Blacks, 14 Indians, 37 females, 3 males) with evidence of renal involvement underwent clinical assessment and percutaneous renal biopsy. Special investigations included: urinary protein quantitation; radioisotope glomerular filtration rate (GFR); complement levels, and antinuclear antibodies and ACAs. Histology was reviewed by a single senior pathologist blinded to the ACA results. In addition to the standard WHO classification, specimens were examined for intrarenal thrombosis. RESULTS: The prevalence of ACA was 45% (18 of 40 patients). Thrombocytopenia was more frequent in patients with ACA (33 vs. 13.6%, p = 0.015). Patients with ACA did not differ from controls with regard to the incidence of thrombosis, neurological disorders, recurrent fetal loss, active disease and hypertension. Mean GFR and 24-hour urine protein (ACA vs. controls) were 51.3 versus 67 ml/min (NS) and 2.4 versus 3.7 g (NS), respectively. Intrarenal microvascular thrombosis (glomerular and arteriolar) occurred in 27.7% of ACA patients versus 9% of controls (p = 0.025). Apart from a higher incidence of class-III nephritis in the controls, standard histology (WHO classification) did not differ between the 2 groups. CONCLUSION: The prevalence of ACA in our patients with lupus nephritis was 45%. This subgroup did not differ from patients without the antibody apart from a higher incidence of thrombocytopenia and intrarenal microvascular thrombosis.