Effect of Cholinesterase Inhibitors on Mortality in Patients With Dementia

BACKGROUND AND OBJECTIVES: Cholinesterase inhibitors (ChEIs) have cardiovascular effects in addition to their neurologic activity and might alter mortality. We wanted to know whether treatment with ChEIs modifies mortality in patients with dementia. METHODS: We searched PubMed, Embase, Cochrane CENTRAL, ClinicalTrials.gov, and ICRTP, from their inception to November 2021, and screened bibliographies of reviews, guidelines, and included studies. We included randomized controlled trials (RCTs) and nonrandomized controlled studies at lower risk of bias comparing ChEI treatment with placebo or usual treatment, for 6 months or longer, in patients with dementia of any type. Two investigators independently assessed studies for inclusion, assessed their risk of bias, and extracted data using predefined forms. Any discordance between investigators was solved by discussion and consensus. Data on all-cause and cardiovascular mortality, measured as either crude death rates or multivariate adjusted hazard ratios (HRs), were pooled using a random-effect model. Information size achieved was assessed using trial sequential analysis (TSA). We followed Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. RESULTS: Twenty-four studies (12 RCTs, 12 cohorts, mean follow-up 6-120 months), cumulating 79,153 patients with Alzheimer (13 studies), Parkinson (1), vascular (1), or any type (9) dementia, fulfilled inclusion criteria. Pooled all-cause mortality in control patients was 15.1 per 100 person-years. Treatment with ChEIs was associated with lower all-cause mortality (unadjusted risk ratio RR 0.74, 95% CI 0.66-0.84; adjusted HR 0.77, 95% CI 0.70-0.84, moderate-quality to high-quality evidence). This result was consistent between randomized and nonrandomized studies and in several sensitivity analyses. No difference appeared between subgroups by type of dementia, age, individual drug, or dementia severity. Less data were available for cardiovascular mortality (3 RCTs, 2 cohorts, 9,182 patients, low-quality to moderate-quality evidence), which was also lower in patients treated with ChEIs (unadjusted RR 0.61, 95% CI 0.40-0.93, adjusted HR 0.47, 95% CI 0.32-0.68). In TSA analysis, the results for all-cause mortality were conclusive but not those for cardiovascular mortality. DISCUSSION: There is moderate-quality to high-quality evidence of a consistent association between long-term treatment with ChEIs and a reduction in all-cause mortality in patients with dementia. These findings may influence decisions to prescribe ChEIs in those patients. TRIAL REGISTRATION INFORMATION: This systematic review was registered in the PROSPERO international prospective register of systematic reviews with the number CRD42021254458 (June 11, 2021).