In the first large study of antihypertensive drug regimens to include a substantial number of black participants, initial treatment with thiazide-type diuretics was found to be equally or more effective as treatment with calcium channel blockers or angiotensin-converting enzyme (ACE) inhibitors for preventing death and morbidity from hypertensive cardiovascular disease. This result held for both black and nonblack participants, leading the researchers to conclude that thiazide-type diuretics "are indicated as the drug of choice for initial therapy for hypertension" in all patients.
The findings were based on data collected between 1994 and 2002 on 33,357 U.S. and Canadian patients, a subgroup of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (better known as the ALLHAT). Participants were 55 years of age or older and had hypertension and at least one other cardiovascular risk factor. Thirty-five percent of participants identified themselves as black; for the purposes of this analysis, participants identifying themselves as white, Asian, Native American, or "other" were combined as nonblack (of these, 92% were white). For all patients, the goal was to reduce blood pressure and maintain it at lower than 140/90 mmHg.
Participants were randomized to receive chlorthalidone, a thiazide-type diuretic; amlodipine, a calcium channel blocker; or lisinopril, an ACE inhibitor. After initial dosages were established by titration, patients were seen every three months for one year and every four months thereafter. Some patients received additional drugs as needed, including atenolol, reserpine, or clonidine, and if necessary, hydralazine. The mean follow-up period was 4.9 years. The primary outcome measure was combined fatal coronary heart disease or nonfatal myocardial infarction. There were several secondary outcomes measured alone or in combination, including stroke, end-stage renal disease, cardiovascular disease (including heart failure, angina, and peripheral vascular disease), and death from all causes.
In both groups, fatal and nonfatal heart failure rates were lowest among those taking diuretics, and this was still the case at six years' follow-up. The only notable difference in findings between blacks and nonblacks pertained to stroke: black patients taking diuretics had a significantly lower incidence of stroke than did black patients taking ACE inhibitors; this difference was not seen in nonblack patients.-Sylvia Foley, senior editor
Wright JT, et al. JAMA 2005;293(13):1595-608.