Association between renin-angiotensin-aldosterone system inhibitors and risk of dementia: A meta-analysis

Objective: To evaluate the association of all RAAS inhibitors, ACE inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) on dementia onset (any dementia, Alzheimer's disease and vascular dementia) using a metaanalytic approach. Methods: A systematic MEDLINE search was carried out to identify all observational studies published up to the 30th September 2020 evaluating the association between RAAS inhibitors and risk of dementia. Studies were included if original investigations considering incident dementia cases, with ACEIs and/or ARBs as exposure and other antihypertensives (AHs) use as reference, and if reporting association estimates and relative variability measures. Random effect pooled relative risks (pRR) and the corresponding 95% confidence intervals (95%CI) were calculated according to DerSimonian and Laird's (DL) or to Hartung Knapp Sidik Jonkman (HKSJ) method depending on the number of studies and between-studies heterogeneity. A linear mixed meta-regression model (MM) was applied to take into account correlation among association estimates from the same study. Results: 15 studies were included in the meta-analysis. ARBs but not ACEIs' use led to a significant reduction of the risk of any dementia (pRR 0.78, 95%CIMM 0.70-0.87) and Alzheimer's disease (pRR 0.73, 95%CIMM 0.60-0.90). Moreover, when compared to ACEIs, ARBs reduced of 14% the risk of any dementia (pRR 0.86, 95% CIDL 0.79-0.94). Conclusions: ARBs but not ACEIs led to a reduction in the risk of any dementia. The difference between ARBs and ACEIs in terms of preventive effectiveness could be due to distinct profiles of antagonism towards independent receptor pathways or to differential influences on amyloid metabolism.