Experiences from hypertension trials--effects on stroke and coronary heart disease.

This review summarises the results of major hypertension trials and addresses the major questions of whether stroke and coronary heart disease (CHD) can be prevented or postponed by blood pressure-lowering drug treatment. Several studies from the 1970s to the 1980s have shown beyond doubt that treatment of high blood pressure decreases the incidence of stroke. Most trials have used thiazide diuretics as active treatment; in one trial the beta-blocker propranolol, compared with placebo, was shown to lower stroke incidence. For thiazide diuretics the preventive effect has been shown for severe, moderate and mild hypertension. The situation regarding CHD is unclear. Early trials with thiazide diuretics showed a lower CHD mortality compared with placebo but no effect on total incidence of CHD events. Three trials during the early 1980s comparing thiazide diuretics and beta-blockers were not able to show a differential effect of the 2 types of drugs. Recently, however, a trial using the cardioselective beta-blocker metoprolol reported a significantly lower CHD mortality and total mortality compared with thiazide diuretics. Further analyses are needed before the question of whether beta-blockers are superior to thiazide diuretics in preventing CHD can be finally answered.