Long Term Effects of Cholinesterase Inhibitors on Cognitive Decline and Mortality.

OBJECTIVE To investigate whether Cholinesterase inhibitors (ChEIs) are associated with slower cognitive decline in Alzheimer's dementia, and decreased risk of severe dementia or death. METHODS Alzheimer's dementia patients from the Swedish Dementia Registry (SveDem) starting on ChEIs within three months of the dementia diagnosis were included and compared to non-treated Alzheimer's dementia patients. In a propensity score matched cohort, the association between ChEI-use and cognitive trajectories assessed by MMSE scores were examined with a mixed model, and severe dementia (MMSE<10) or death as outcomes with Cox proportional hazards models. RESULTS The matched cohort included 11,652 ChEI-users and 5,826 non-users. During an average of 5 years follow up, 255 cases developed severe dementia and 6,055 (35%) died. ChEI-use was associated with higher MMSE at each visit (0.13 MMSE points/year; 95% confidence interval-CI 0.06, 0.20). ChEI-use had a 27% lower risk of death (0.73; CI 0.69, 0.77) compared with non-users. Galantamine was associated with lower risk of death (0.71; CI 0.65, 0.76), lower risk of severe dementia (0.69; CI 0.47-1.00), and had the strongest effect on cognitive decline of all the ChEIs (0.18 MMSE points/year, CI 0.07, 0.28). CONCLUSIONS ChEIs are associated with cognitive benefits which are modest but persist over time and with reduced mortality risk, which could be explained partly by their cognitive effects. Galantamine was the only ChEI demonstrating a significant reduction in the risk of developing severe dementia. CLASSIFICATION OF EVIDENCE This study provides Class III evidence that for patients with Alzheimer's dementia, ChEIs decrease long term cognitive decline and risk of death, and that galantamine decreases the risk of severe dementia.