Association between comorbidity burden and rapid cognitive decline in individuals with mild to moderate Alzheimer's disease

Abstract

Objectives: To determine the association between rapid cognitive decline and burden of comorbidities as assessed using the Charlson Comorbidity Index in individuals aged 65 and older with Alzheimer's disease (AD).

Design: Retrospective cohort study.

Setting: Memory clinic at the University Hospital of Nantes.

Participants: Individuals aged 65 and older with AD (n=170).

Measurements: Subjects were followed for 1 year. Rapid cognitive decline was defined as a decrease of 3 or more points on the Mini-Mental State Examination per 12-month period. Variables studied were the Charlson Comorbidity Index (measure of comorbidity burden), age, sex, AD stage, type of residence (living at home or not), presence of caregiver, functional abilities (Lawton and Katz scales), risk of malnutrition or depression, and intercurrent events (hospitalization or initiating home care).

Results: Rapid cognitive decline at 1-year follow-up occurred in 65 subjects (38.2%). In fully adjusted logistic regression analysis, Charlson Comorbidity Index was significantly associated with rapid cognitive decline (odds ratio (OR)=1.30, P=.03). Moderate stage of AD (OR=2.07, P=.04) and living at home (OR=4.17, P=.04) were also associated with rapid cognitive decline.

Conclusion: Comorbidity burden was associated with rapid cognitive decline in subjects with AD.

Keywords: Alzheimer's disease; comorbidity; rapid cognitive decline.