Association of baseline dementia stage with cognitive markers during follow‐up in patients with dementia of Alzheimer type with and without post‐mortem Alzheimer pathology

AbstractBackgroundPrediction of the course of cognitive function is of central importance in the care of patients with dementia of Alzheimer type (DAT) for individual management, counseling and treatment. Baseline clinical examination and cognitive function testing are decisive in the classification of the dementia type and stage, but their predictive value to foresee the future course of the disease is critical. This project aims to examine the relationship of baseline dementia stage and Alzheimer’s disease neuropathological changes (ADNC) at autopsy with cognitive function during the course of the disease.MethodThis study is based on longitudinal data from The National Alzheimer‘s Coordinating Center (NACC)‐Uniform and Neuropathology Data Set. Participants were retrospectively included based on the following criteria: Clinical diagnosis of DAT, cognitive function testing by Mini‐Mental State Examination (MMSE), and report of ADNC at autopsy (ABC score). Baseline dementia stages were defined by the MMSE score (≥27/20‐26/10‐19/≤9). Neuropathological diagnosis of Alzheimer’s disease was defined by ABC score levels “High” or “Intermediate” (confirmed‐ADNC) as opposed to ABC score levels “Low” or “Not” (no‐ADNC).ResultOf 44,359 participants, 1,469 met inclusion criteria with 5,649 cognitive data points (i. e., on average 4.6±1.9 MMSE scores/participant). At baseline, 33%/49%/16%/2% of participants were assigned MMSE ranges of ≥27/20‐26/10‐19/≤9 respectively. The proportion of confirmed‐ADNC within the respective groups increased as a function of the baseline MMSE range (76%/90%/95%/96% respectively). Cognitive function changes from baseline to last visit depended on the neuropathological diagnosis (‐7 vs. ‐4 MMSE score points for confirmed‐ADNC vs. no‐ADNC respectively), but not on MMSE score at baseline (all ‐7 score points). Participants with a baseline MMSE score ≤9 decreased even less (‐3 score points).ConclusionThe present descriptive analysis does not provide evidence for a clear association of cognitive function decline during follow‐up and baseline MMSE scores, in contrast to ADNC which predicted faster decline, in patients with DAT. Modelling analyses including covariates will be presented.