Antihypertensive treatment and prevention of stroke and dementia

Abstract

Hypertension is the most consistent and powerful predictor of stroke and is involved in nearly 70% of strokes. Placebo-controlled trials have proven that blood-pressure-lowering treatment reduces the incidence of stroke by 40% in middle-aged or older hypertensive patients with predominantly diastolic hypertension and by 30% in older patients with isolated systolic hypertension. Recent trials have compared new agents (calcium-channel blockers, α-blockers, angiotensin converting enzyme inhibitors or angiotensin type-1 receptor blockers) with old durg classes (diuretics or β-blockers). Calcium-channel blockers, including (−8%, P=0.07) or excluding verapamil (−10%, P=0.02), as well as angiotensin type-1 receptor blockers (−24%, P=0.0002) resulted in better stroke prevention than did the old drugs, whereas the opposite trend was observed for angiotension converting enzyme inhibitors (+10%, P=0.03). An overview of 6 trials conducted in patients with a history of cerebrovascular disease demonstrated that antihypertensive drug treatment reduced stroke recurrence by 25% (P=0.004). A meta-regression analysis showed that within-trial differences in systolic blood pressure accounted for the prevention of stroke in most trials. In 5 trials, dementia was a secondary outcome. Overall, antihypertensive treatment did not reduce the incidence of vascular or degenerative dementia (−11%, P=0.15). However, when the analysis was limited to 3 trials involving a dihydropyridine or a diuretic as the mainstay of therapy, this benefit increased to 25% (P=0.01). Randomized clinical trials should urgently address the question to what extent blood-pressure-lowering therapy may prevent degenerative dementia.