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

Abstract

Black people have a greater prevalence of elevated blood pressure leading to excess morbidity and mortality. To systematically review the effects of different antihypertensive drugs on mortality, morbidity and blood pressure black adults with elevated blood pressure. Medline, Embase, LILACS, African Index Medicus, the Cochrane Library November 2003; Pubmed September 2003 to March 2004. Searches were conducted without language restriction. Randomised controlled trials of drugs versus placebo (blood pressure outcomes) or versus placebo or other drugs (morbidity and mortality outcomes). Two reviewers independently extracted data unblinded. Disagreements were resolved by discussion. Authors were contacted twice to obtain missing information. 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. 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.