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Reducing Blood Pressure Prevents Dementia

Prevention of dementia may emerge as a new indication for antihypertensive therapy. Dr. Lennart Hansson predicted at the 24th Congress of the European Society of Cardiology.

And there’s another related emerging indication: prevention of further cognitive decline in patients with mild cognitive dysfunction, added Dr. Hansson, professor of clinical hypertension research at the University of Uppsala, Sweden.

Dr. Hansson, who presented this year’s annual Denolin Lecture on clinical cardiology, cited intriguing new evidence in support of these predictions. For example, in the soon-to-be-published Study on Cognition and Prognosis in the Elderly (SCOPE), hypertensive subjects with normal to slightly compromised cognitive function at baseline demonstrated significantly better preservation of cognitive function with candesartan than with diuretic-based blood pressure lowering over a 3- to 5-year follow-up.

Dr. Hansson served as cochair of SCOPE, a 15-nation study in which 4,937 mildly hypertensive patients aged 70-89 were randomized to the angiotensin-receptor blocker candesartan or diuretic-based therapy. Serial Mini-Mental Status Exams (MMSEs) conducted during more than 18,000 patient-years of follow-up showed that among patients with a baseline MMSE of 24-28—indicative of normal to slightly impaired cognitive function—those in the candesartan arm had a mean 0.5-point decline in MMSE scores during follow-up, compared with a 6-point drop in those on a diuretic. The cognitive benefit was even more pronounced in patients over age 85.

Candesartan was as effective as diuretic-based therapy for prevention of MIs in SCOPE. The total stroke rate was significantly lower with candesartan, though—9.7%, compared with 12.8% in controls. And the incidence of nonfatal stroke was 28% lower in the candesartan arm—7.4%, compared with 10.3%.

Other recent data suggesting a possible role for blood pressure lowering in prevention of dementia come from the 6,105-patient Perindopril Protection Against Recurrent Stroke Study (PROGRESS). Dr. Hansson, a regional principal investigator in this landmark trial, said a PROGRESS substudy now in press showed that stroke patients randomized to perindopril plus indapamide had a significantly lower incidence of dementia than those on placebo during a mean 4 years of follow-up. This was true regardless of whether these stroke survivors were normotensive or hypertensive at baseline.

The Systolic Hypertension–Europe trial showed convincingly that lowering blood pressure in elderly patients with isolated systolic hypertension protects against dementia, he added.

The suggestion that blood pressure lowering protects against dementia runs counter to traditional thinking among neurologists, who have asserted that low blood pressure is a risk factor for dementia. It’s far more likely, according to Dr. Hansson, that low blood pressure is a consequence of the physical inactivity, weight loss, sensory deprivation, and decreased sympathetic outflow inherent in dementia.

He pointed to a longitudinal study of a cohort of patients with Alzheimer’s disease from Gothenburg, Sweden, that showed 15 years prior to their diagnosis their systolic pressures were an average of nearly 20 mm Hg higher and their diastolic pressures were 10 mm Hg higher.