Penbutolol in the treatment of mild to moderate essential hypertension in black South Africans

Pharmacotherapy for hypertension in Sub-Saharan Africa: a systematic review and network meta-analysis

BACKGROUND

The highest burden of hypertension is found in Sub-Saharan Africa (SSA) with a threefold greater mortality from stroke and other associated diseases. Ethnicity is known to influence the response to antihypertensives, especially in black populations living in North America and Europe. We sought to outline the impact of all commonly used pharmacological agents on both blood pressure reduction and cardiovascular morbidity and mortality in SSA.

METHODS

We used similar criteria to previous large meta-analyses of blood pressure agents but restricted results to populations in SSA. Quality of evidence was assessed using a risk of bias tool. Network meta-analysis with random effects was used to compare the effects across interventions and meta-regression to explore participant heterogeneity.

RESULTS

Thirty-two studies of 2860 participants were identified. Most were small studies from single, urban centres. Compared with placebo, any pharmacotherapy lowered SBP/DBP by 8.51/8.04 mmHg, and calcium channel blockers (CCBs) were the most efficacious first-line agent with 18.46/11.6 mmHg reduction. Fewer studies assessing combination therapy were available, but there was a trend towards superiority for CCBs plus ACE inhibitors or diuretics compared to other combinations. No studies examined the effect of antihypertensive therapy on morbidity or mortality outcomes.

CONCLUSION

Evidence broadly supports current guidelines and provides a clear rationale for promoting CCBs as first-line agents and early initiation of combination therapy. However, there is a clear requirement for more evidence to provide a nuanced understanding of stroke and other cardiovascular disease prevention amongst diverse populations on the continent.

TRIAL REGISTRATION

PROSPERO, CRD42019122490. This review was registered in January 2019.

Systematic review: antihypertensive drug therapy in patients of African and South Asian ethnicity

Despite the large differences in the epidemiology of hypertension across Europe, treatment strategies are similar for national populations of white European descent. However, hypertensive patients of African or South Asian ethnicity may require ethnic-specific approaches, as these population subgroups tend to have higher blood pressure at an earlier age that is more difficult to control, a higher occurrence of diabetes, and more target organ damage with earlier cardiovascular mortality. Therefore, we systematically reviewed the evidence on antihypertensive drug treatment in South Asian and African ethnicity patients. We used the Cochrane systematic review methodology to retrieve trials in electronic databases including CENTRAL, PubMed, and Embase from their inception through November 2015; and with handsearch. We retrieved 4596 reports that yielded 35 trials with 7 classes of antihypertensive drugs in 25,540 African ethnicity patients. Aside from the well-known blood pressure efficacy of calcium channel blockers and diuretics, with lesser effect of ACE inhibitors and beta-blockers, nebivolol was not more effective than placebo in reducing systolic blood pressure levels. Trials with morbidity and mortality outcomes indicated that lisinopril and losartan-based therapy were associated with a greater incidence of stroke and sudden death. Furthermore, 1581 reports yielded 16 randomized controlled trials with blood pressure outcomes in 1719 South Asian hypertensive patients. In contrast with the studies in African ethnicity patients, there were no significant differences in blood pressure lowering efficacy between drugs, and no trials available with mortality outcomes. In conclusion, in patients of African ethnicity, treatment initiated with ACE inhibitor or angiotensin II receptor blocker monotherapy was associated with adverse cardiovascular outcomes. We found no evidence of different efficacy of antihypertensive drugs in South Asians, but there is a need for trials with morbidity and mortality outcomes. Screening for cardiovascular risk at a younger age, treating hypertension at lower thresholds, and new delivery models to find, treat and follow hypertensives in the community may help reduce the excess cardiovascular mortality in these high-risk groups.

WITHDRAWN: Effect of antihypertensive drugs on mortality, morbidity and blood pressure in blacks

BACKGROUND

Black people have a greater prevalence of elevated blood pressure leading to excess morbidity and mortality.

OBJECTIVES

To systematically review the effects of different antihypertensive drugs on mortality, morbidity and blood pressure black adults with elevated blood pressure.

SEARCH STRATEGY

Medline, Embase, LILACS, African Index Medicus, the Cochrane Library November 2003; Pubmed September 2003 to March 2004. Searches were conducted without language restriction.

SELECTION CRITERIA

Randomised controlled trials of drugs versus placebo (blood pressure outcomes) or versus placebo or other drugs (morbidity and mortality outcomes).

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data unblinded. Disagreements were resolved by discussion. Authors were contacted twice to obtain missing information.

MAIN RESULTS

Full reports or abstracts from more than 2900 references of papers yielded 30 trials considering 53 interventions with 8 classes of antihypertensive drugs in 20,006 black patients from Africa, the Caribbean, and the United States of America, aged 18 to >80 years. In one large trial the main morbidity and mortality outcomes did not differ significantly between initial treatment drug classes when drugs were added to reach goal blood pressures. However, the comparison ACE Inhibitors vs diuretic favoured the diuretic for stroke 1.40 [1.17 to 1.68]; combined CHD 1.15 [1.02 to 1.30] and combined CVD 1.19 [1.09 to 1.30] and the comparison alpha blocker vs diuretic favoured the diuretic for combined CVD 1.40 [1.25 to 1.57]. In addition, all comparisons for heart failure favoured diuretic (1.47 [1.24 to 1.74] vs calcium blocker; 1.32 [1.11 to 1.58] vs ACE Inhibitor; and 2.18 [1.73 to 2.74] vs alpha blocker. The results also showed a greater occurrence of diabetes with diuretics. No significant differences were detected between placebo and beta adrenergic blockers in the reduction of systolic blood pressure (weighted mean difference [95% CI], -3.52 [-7.50 to 0.46] mm Hg). In addition, ACE inhibitors did not significantly differ from placebo in achievement of goal diastolic blood pressure (risk difference [95% CI], 5% [-10% to 21%]). Calcium blockers, diuretics, centrally acting agents, alpha adrenergic blockers and angiotensin II antagonists were all more effective than placebo in reducing blood pressure in the pooled analyses. Only calcium blockers remained effective in all prespecified subgroups, including baseline diastolic blood pressure >109 mm Hg.

AUTHORS' CONCLUSIONS

When first-line drugs from different classes are compared in the treatment of black people, there is no evidence of differential effects on most mortality and morbidity outcomes. Those morbidity differences that were found favoured diuretics. Drugs differ in their ability to reduce blood pressure in black people. Calcium blockers were the only drug class that reduced blood pressure in all subgroups of black people including those with severe hypertension. Beta-blockers, angiotensin receptor blocker, alpha blockers and ACE Inhibitors were least good at reducing blood pressure in black adults.

Use of beta-adrenergic receptor blockers in blacks

Beta adrenergic receptor blockers (beta-blockers) are an important class of drugs in the management of patients with cardiovascular diseases. These drugs have been shown to reduce mortality in hypertension and prolong survival in patients with coronary heart disease. Although hypertension and coronary heart disease account for the majority of excess cardiovascular morbidity and mortality in blocks, beta-blockers continue to be underprescribed in this ethnic group. The magnitude of blood pressure reduction in black patients with hypertension has been consistently less during monotherapy with nonselective beta-blockers than with diuretics. However, the highly selective beta-blocker bisoprolol has been shown to be as effective as diuretics and is equally effective in black and nonblack patients with hypertension. In general, no racial differences in efficacy are noted when beta-blockers are used with diuretics as combination therapy for hypertension. Black patients should not be denied beta-blocker therapy because of an anticipated suboptimal response, especially when there are clear indications for treatment (e.g., for migraine, hyperthyroidism, arrhythmia control, and after myocardial infarction).