Background: Hypertension is associated with impaired cognitive function but the effect of antihypertensive treatment on cognitive function is unclear.
Methods: We investigated the effect of treatment of hypertension on cognition with the angiotensin-receptor-blocker, candesartan, in a placebo-controlled, double-blind, randomized controlled trial at one center participating in the Study on Cognition and Prognosis in the Elderly. A total of 257 older adults with hypertension (mean age 76 years, blood pressure 165 +/- 8/88 +/- 7 mm Hg) were recruited from general practice and treated with 8-16 mg candesartan or placebo once daily, for a mean follow-up period of 44 months. Additional antihypertensive therapy was permitted in both groups to achieve treatment targets. Cognitive function was measured using the Cognitive Drug Research computerized assessment battery, trail-making tests, and verbal fluency. Data from annual assessments were used to calculate individual coefficients of decline by regressing composite test scores over time for five cognitive domains.
Results: The blood pressure difference between groups at study close was 8/3 mm Hg. The candesartan group showed less decline in attention (0.004 vs -0.036, p = 0.04) and episodic memory (0.14 vs -0.22, p = 0.04) compared to placebo, a similar trend for speed of cognition (-2.3 vs -17.4, p = 0.15), but no differences in working memory (0.0014 vs 0.0010, p = 0.90) or executive function (-0.0031 vs -0.0023, p = 0.95). Effect sizes were in the small-to-moderate range.
Conclusions: The potential for blood pressure-lowering with angiotensin-receptor-blockers to reduce the rate of decline of specific areas of cognitive function in older patients with hypertension warrants further investigation to determine clinical efficacy.