Risk of Dementia During Antihypertensive Drug Therapy in the Elderly.

Background: Evidence exists that lowering high blood pressure reduces the risk of dementia. However, the generalizability of this evidence to old patients from the general population remains uncertain.

Objectives: This study sought to evaluate the effect of antihypertensive drug treatment on the risk of dementia in a heterogeneous group of new users of antihypertensive drugs.

Methods: A nested case-control study was carried out by including the cohort of 215,547 patients from Lombardy, Italy, aged ≥65 years, who started taking antihypertensive drugs between 2009 and 2012. Cases were the 13,812 patients (age 77.5 ± 6.6 years; 40% men) who developed dementia or Alzheimer's disease during follow-up (up to 2019). For each case, 5 control subjects were selected to be matched for sex, age, and clinical status. Exposure to drug therapy was measured by the proportion of the follow-up covered by antihypertensive drugs. Conditional logistic regression was used to model the outcome risk associated with exposure to antihypertensive drugs.

Results: Exposure to treatment was inversely associated with the risk of dementia. Compared with patients with very low exposure, those with low, intermediate, and high exposure exhibited a 2% (95% CI: -4% to 7%), 12% (95% CI: 6%-17%), and 24% (95% CI: 19%-28%) risk reduction, respectively. This was also the case for very old (aged ≥85 years) and frail patients (ie, those characterized by a high mortality risk at 1 year).

Conclusions: In the old fraction of the general population, antihypertensive drug treatment is associated with a lower risk of dementia. This was also the case in very old and frail patients.