OBJECTIVES: To estimate the associations between CDR scores and meaningful outcomes (e.g., activities of daily living using Functional Assessment Scale [FAS] and other cognitive scales) in individuals followed at Alzheimer’s disease (AD) research centers

METHODS: This retrospective study used the National Alzheimer’s Coordinating Center (NACC) Uniform Data Set (UDS), which collects yearly follow-up data from patients that are seen at participating AD research centers. The study included participants with normal cognition, MCI or dementia due to AD (etiologies were determined by clinician diagnosis). The associations between the annual assessments of CDR-global and the meaningful outcomes were investigated using mixed models with unstructured covariance matrices and participant identifiers as random effects adjusting for demographics and comorbidities.

RESULTS: The study included participants with normal cognition (13,692 [48.5%]); MCI (7,075 [25.1%]); and dementia due to AD (7,453 [26%]). Difficulties in conducting daily activities such as writing checks, doing grocery shopping, or preparing a hot meal were observed in participants with MCI (CDR-global=0.5) and across all stages of dementia (CDR-global>1) due to AD. Further, the adjusted total baseline FAS average scores (higher values indicate worse function) were 1.7 CI [1.4, 2.0], 7.2 CI [6.9, 7.5], 18.3 CI [18.0, 18.6], 25.7 CI [25.4, 26.0] and 28.8 CI [28.4, 29.1] for normal, MCI, mild, moderate, and severe AD dementia, respectively. Similar patterns were observed for all other outcomes of interest (e.g. geriatric depression scale and Mini-Mental State Exam).

CONCLUSIONS: There were strong associations between CDR-stage and different measures of mental health, cognition and ability to conduct daily activities in patients with AD. CDR-global is a good proxy for abilities considered clinically meaningful in MCI and mild AD dementia