BP-lowering medications help fight dementia

Controlling elevated blood pressure (BP) with antihypertensive drugs appears to have another benefit, which is to lower the risk of dementia, according to the results of a meta-analysis.

Researchers performed a systematic review of prospective observational studies investigating the association between BP variables/BP-lowering drugs and cognitive disorders (all-cause dementia, Alzheimer’s disease [AD], vascular dementia [VaD], or cognitive impairment) among participants with normal cognition or mild cognitive impairment.

The meta-analysis included 136 studies, of which 132 were prospective cohort, three were case–control, and one was a case-cohort study. The total population consisted of 2,214,814 individuals (46.6 percent female), with the mean age ranging from 35.3 to 93.2 years. Mean follow-up duration varied between 1.5 and 43 years.

There were 10 BP-related risk factors identified for cognitive disorders. These were hypertension, prehypertension, systolic BP, diastolic BP, systolic BP variability, diastolic BP variability, diastolic BP change, orthostatic hypotension, pulse pressure, and BP-lowering drugs.

Pooled data revealed that BP influenced cognitive disorders, with stronger associations observed in midlife than in late-life. Specifically, moderate-quality evidence showed that midlife hypertension heightened the risk of cognitive disorders by 19 percent to 55 percent. Dose-response analyses of five studies indicated that midlife systolic BP >130 mm Hg conferred an increased risk of cognitive disorders.

With respect to late-life BP, high systolic BP, low diastolic BP, excessive BP variability, and orthostatic hypotension all emerged as risk factors for increased dementia risk.

Conversely, the use of antihypertensive medications reduced the risk by about 21 percent. The U-shaped dose-response curve suggested that the protective window of diastolic BP level was between 90 and 100 mm Hg for a low risk of Alzheimer’s disease. The associations between BP variables and cognitive disorders were influenced by age and BP type.

More studies are needed to determine the optimal dose, duration, and type of BP-lowering drugs for preventing cognitive disorders, according to the researchers.