The aim of the vascular dementia project, set up in the framework of the double-blind placebo-controlled Systolic Hypertension in Europe (Syst-Eur) trial, was to investigate the influence of antihypertensive drug treatment on the incidence of vascular dementia. The study was run on non-demented patients, at least 60 years old, with isolated systolic hypertension (sitting blood pressure of 160-219 mmHg for systolic and below 95 mmHg for diastolic). Treatment was initiated with nitrendipine (10-40 mg/day) possibly associated with enalapril (5-20 mg/day) and/or hydrochlorothiazide (12.5-25 mg/day). Cognitive function was assessed at baseline and annually by the Mini Mental State Examination (MMSE). The diagnosis of dementia was based on the DSM-III-R criteria. The etiology of dementia was established using the Modified Ischemic Score or the Hachinski score when brain imaging was not available. Median follow-up by intention-to-treat was 2.0 years. The incidence of dementia was reduced by 50% from 7.7 per 1000 patient-years in the placebo group (number of patients 1,180) to 3.7 cases per 1000 p-a in the active treatment group (n = 1,238) (21 vs 11 patients, p = 0.05). At the last available evaluation, systolic and diastolic blood pressure were 8.3 mmHg and 3.8 mm Hg lower (p < or = 0.001) in the active-treatment group, but on average the MMSE scores remained stable in both groups.
Conclusion: In older people with isolated systolic hypertension, antihypertensive treatment started with nitrendipine may reduce the incidence of dementia. At the rate observed in the placebo group, treating 1,000 patients for 5 years would prevent 19 cases of dementia.