Hypertension, hypotension, longevity and dementia.

Abstract

High blood pressure at midlife has been consistently identified as a risk factor for dementia in late life, while dementia onset is typically associated with a subsequent decline of blood pressure values. A previous meta-analysis of randomized controlled studies of anti-hypertensive treatment in old age has shown a borderline effect of active treatment in reducing the risk of dementia. The cognitive sub-studies of SPRINT (SPRINT-MIND) and of HOPE-3, published in 2019, were aimed at assessing the cognitive effect of aggressive antihypertensive treatment. In SRINT-MIND, that included subjects with high vascular risk, the risk of dementia (primary outcome) did not differ between groups, but the risk of mild cognitive impairment was significantly reduced in the treatment group. Conversely in HOPE-3, that included subjects with intermediate vascular risk, no significant cognitive effect was observed, with a trend for a better outcome in the placebo arm in the subgroup with lower baseline systolic blood pressure. These data add to observational studies showing detrimental cognitive effect of lower blood pressure values in very old subjects, with cognitive impairment, disability, and complex health problems. Regarding longevity, observational studies confirm protective effects of lower blood pressure values, although systolic blood pressure <130 mmHg are associated with greater mortality risk in subjects with cognitive and/or motor impairment. On the whole antihypertensive treatment might decrease the risk of cognitive impairment in older, robust, high vascular risk subjects. Yet the presence of cognitive impairment might modify the prognostic effect of antihypertensive treatment and advise against aggressive blood pressure lowering.