Hypertension treatment trials and stroke occurrence revisited. A quantitative overview.

To provide further understanding of the decline in stroke mortality in the United States, data from 16 randomized controlled trials of hypertension treatment and stroke published to date are pooled. The overall weighted average blood pressure reduction was 13/6 mm Hg. The pooled odds ratio was 0.61 (95% confidence interval: 0.55, 0.68), indicating approximately a 39% (32 to 45%) reduction in stroke occurrence. Percent reduction was somewhat higher in studies of mild-moderate hypertension (47%) and somewhat lower in studies of the elderly (35%). There was no differential effect by gender (reductions of 37% for women, 34% for men) or by race (32% for blacks, 37% for whites). The magnitudes of reductions for fatal (41%) and nonfatal (37%) strokes, and for diuretics and beta-blockers (odds ratio diuretic versus beta-blocker, 0.86; 95% CI: 0.69, 1.08) were similar. Implications for the decline in stroke mortality in the United States are discussed.