Angiotensin-Converting Enzyme Inhibitors and Cognitive Decline in Older Adults With Hypertension

Abstract

The prevalence of Alzheimer disease (AD) in the United States is projected to increase to approximately 9 to 13 million by 2050.^1,2 Conservative estimates project that 2 new cases will be diagnosed every minute in the United States by then and that delaying the onset of dementia, even by 1 year, would have a substantial impact on public health, reducing the number of cases over 10 years by an estimated 210 000.² Hypertension (HTN) is an important risk factor for the development of dementia, of both the vascular and the Alzheimer types.^3-5 Epidemiological data from large cohort studies have typically shown an association between the use of anti-HTN drugs and a lower risk of dementia.^6-8 However, controlled trials of commonly used classes of anti-HTN drugs (calcium channel blockers, β-blockers, diuretics, and angiotensin-converting enzyme [ACE] inhibitors) have yielded mixed results with respect to their protective effect on the incidence of dementia.^9-12 Also, a Cochrane meta-analysis found that blood pressure reduction (by all drug classes combined) was not significantly associated with a reduced risk of cognitive impairment or dementia.¹³ Therefore, it raises the question of whether a mechanism independent of (or in addition to) blood pressure lowering accounts for the variable protective effects on cognition that have been described.