Risk factors that affect life expectancy in Alzheimer's disease: a 15-year follow-up

Abstract

Backgrounds/aims: Future disease-modifying therapies might affect the expected life span in Alzheimer's disease (AD). Our aim was to identify factors that influence life expectancy in cholinesterase inhibitor (ChEI)-treated patients.

Methods: This study included 791 deceased individuals with a clinical diagnosis of AD and a Mini-Mental State Examination score of 10-26 at baseline who were recruited from a 3-year, prospective, multicenter study of ChEI therapy in clinical practice. The participants' date of death was recorded and their survival was compared with the gender- and age-matched general population.

Results: The mean survival time after the start of ChEI therapy (time of AD diagnosis) was 5.10 years for men and 6.12 years for women. Better cognitive ability, less impaired basic functional capacity, and fewer medications, but not education level or apolipoprotein E (APOE) genotype, were independent prognostic factors of longer survival after diagnosis, after controlling for gender and age.

Conclusion: AD shortens life expectancy in ChEI-treated patients diagnosed before the age of 85 years, similar to that reported previously for untreated individuals. A longer life span was observed in the eldest patients (≥85 years) compared with untreated cohorts, which did not differ from that observed in the general population. Higher education or carrying two APOE ε4 alleles were risk factors for earlier death.