Antihypertensive drug use and the risk of dementia in patients with diabetes mellitus

Background: Diabetes and hypertension are independent risk factors for dementia, and hypertension may increase this risk in patients with diabetes. It is unclear whether antihypertensive drugs are associated with risk of dementia in these patients. Methods: A retrospective study using a national cohort of beneficiaries of the Department of Veterans Affairs who have diabetes examined incidence of dementia over a 2-year follow-up period. Multivariate Cox proportional hazards regression model was used to estimate the unique effects of comorbid hypertension and antihypertensive medications on risk of dementia, after adjusting for several potential confounders. Results: In all, 377,838 patients were studied (mean age: 75.53 +/- 6.07 years). After adjustments were made for sociodemographic factors, duration of diabetes, comorbidity, and comedications, hypertension was associated with increased risk of developing dementia (hazard ratio [HR] = 1.08; 95% confidence interval [CI] = 1.03, 1.14). Antihypertensive medications decreased risk, ranging from 24% for angiotensin receptor blockers (ARBs) to 4% for beta-blockers. In a stratified analysis of patients without hypertension, angiotensin-converting enzyme inhibitors (HR = 0.81; 95% CI = 0.69, 0.94) and ARBs (HR = 0.55; 95% CI = 0.34, 0.88) continued to show protective effects. Conclusions: Comorbid hypertension was associated with increased risk of dementia, whereas antihypertensive medications, especially angiotensin-converting enzyme inhibitors and ARBs, were associated with reduced risk, even among patients without hypertension. Consequently, these agents may have potential therapeutic roles in delaying the onset of dementia in patients with diabetes. (C) 2012 The Alzheimer's Association. All rights reserved.