Survival in Alzheimer disease: a multiethnic, population-based study of incident cases

Abstract

Objective: To describe factors associated with survival in Alzheimer disease (AD) in a multiethnic, population-based longitudinal study.

Methods: AD cases were identified in the Washington Heights Inwood Columbia Aging Project, a longitudinal, community-based study of cognitive aging in Northern Manhattan. The sample comprised 323 participants who were initially dementia-free but developed AD during study follow-up (incident cases). Participants were followed for an average of 4.1 (up to 12.6) years. Possible factors associated with shorter lifespan were assessed using Cox proportional hazards models with attained age as the time to event (time from birth to death or last follow-up). In subanalyses, median postdiagnosis survival durations were estimated using postdiagnosis study follow-up as the timescale.

Results: The mortality rate was 10.7 per 100 person-years. Mortality rates were highest [corrected] among those diagnosed at older ages, and among non-Hispanic whites compared to [corrected] Hispanic [corrected] The median lifespan of the entire sample was 92.2 years (95% CI: 90.3, 94.1). In a multivariable-adjusted Cox model, history of diabetes and history of hypertension were independently associated with a shorter lifespan. No differences in lifespan were seen by race/ethnicity after multivariable adjustment. The median postdiagnosis survival duration was 3.7 years among non-Hispanic whites, 4.8 years among African Americans, and 7.6 years among Hispanics.

Conclusion: Factors influencing survival in Alzheimer disease include race/ethnicity and comorbid diabetes and hypertension.

Figure Kaplan-Meier curves depicting postdiagnosis survival by race/ethnic group