[F3–05–01]: COGNITIVE AND FUNCTIONAL PREDICTORS OF INCIDENT ALZHEIMER'S DISEASE: DATA FROM THE NATIONAL ALZHEIMER's COORDINATING CENTER (NACC)

Impairment in Instrumental Activities of Daily Living (IADLs), together with cognitive performance is useful in determining which individuals with mild cognitive impairment (MCI) are at risk for Alzheimer's disease (AD). We examined the utility of the self-report Functional Assessment Questionnaire (FAQ) in predicting incident AD in a group of racially/ethnically diverse participants from the National Alzheimer's Coordinating Center (NACC) database. Participants were included if they met the following criteria: diagnosis of MCI by a NACC clinician, Clinical Dementia Rating global score=0.5, and impairment on at least one memory and one non-memory test. Cox regression methods were used to estimate AD risk associated with the FAQ and composite scores of verbal memory (Logical Memory I; IIA), Attention (Digit Span Forward; Trails A), Executive Function (Digit Span Backward; Trails B; Digit Symbol), and Language (Semantic fluency; Object naming) as well as a total composite score. Racial/Ethnic groups were analyzed separately to evaluate potential differences in associations between cognitive predictors and AD. 878 participants (713 Non-Hispanic Caucasians, 151 African Americans, 14 Hispanics) were classified as having MCI, based on NIA/AA clinical and cognitive criteria. Participants had an average of 3.5 years (range: 0.5–10.5) of follow-up, which did not differ by race/ethnicity or education; males and older participants were more likely to be in the study for > 3 years. 373 (42.5%) participants progressed from MCI to NINCDS/ADRDA criteria for probable AD. Based on Cox regression models including the full sample, the total composite score predicted incident probable AD (HR 1.05, 95% CI 1.03–1.07). The FAQ (HR 1.37, 95% CI 1.27–1.48), Verbal Memory (HR 1.27, CI 1.19–1.35), and Language (HR 1.08, 95% CI 1.03–1.13) each independently predicted probable AD. The FAQ, Memory, Executive Function, and Language were significant predictors of probable AD for Non-Hispanic Caucasians, but only FAQ was significant for the African American/Hispanic group. Findings support the addition of a measure of mild functional decline, such as the FAQ, as part of criteria for MCI in multi-ethnic/racial populations. Differences in the predictive utility of cognitive domains by race/ethnicity using NIA/AA cognitive and clinical MCI criteria warrant further investigation.