Twelve studies, five RCTs and seven observational studies (n=27,301) were included in the review. Quality assessment results were not reported.
Six studies (two RCTs) found that antihypertensive drugs either reduced the risk of dementia or slowed cognitive decline.
Diuretics: Four out of six studies (two RCTs) found that diuretics were associated with a reduced risk of dementia. Diuretics seemed to be effective in reducing the incidence of Alzheimer’s dementia, vascular dementia and unspecified dementia. There were no data on progression of vascular dementia. Two studies found diuretics beneficial when used in combination with other antihypertensive agents (for example, ACE inhibitors, calcium channel blockers).
ACE inhibitors: Three out of six studies (two RCTs) found ACE inhibitors to have beneficial effects in dementia. ACE inhibitors reduced progression of Alzheimer’s dementia by slowing cognitive decline and reduced incidence of vascular dementia and unspecified dementia. Two RCTs indicated that brain-penetrating ACE inhibitors, particularly perindopril (with/without diuretics), may have been more neuroprotective than non brain-penetrating ACE inhibitors and calcium channel blockers and decreased incidence and progression of dementia.
Other antihypertensive agents: Use of agents from other antihypertensive classes appeared to have no effect on dementia (nine studies).