Performance of study partner reports in a non-demented at-risk sample.

Introduction: The Clinical Dementia Rating (CDR) Scale is a gold standard for staging impairment in Alzheimer's disease and other dementias (ADRD). The Quick Dementia Rating System (QDRS) offers similar results in 3 to 5 minutes without a trained clinician. This study aimed to (1) investigate concordance between comparably derived QDRS and CDR global scores, (2) examine item-level QDRS/CDR agreement, and (3) compare sample characteristics and cognitive performance across QDRS/CDR global concordant/discordant groups.

Methods: The study included 351 QDRS/CDR pairs from 297 participants in the Wisconsin Registry for Alzheimer's Prevention (WRAP). Analyses included descriptive indices of QDRS/CDR agreement, lasso logistic regression, tetrachoric correlations, and linear mixed models.

Results: The QDRS global/CDR global concordance rate is 70.66%. Memory item discrepancies were primarily responsible for QDRS/CDR global rating discordance. Average cognitive scores were highest in concordant-normal QDRS/CDR and lowest in concordant-abnormal QDRS/CDR.

Discussion: The QDRS effectively screened for impairment in this sample. Future analyses will investigate QDRS relations to ADRD biomarkers.

Highlights: The Quick Dementia Rating System (QDRS) effectively screened for impairment in Alzheimer's disease and other dementias (ADRD) in a non-demented sample. Concordance rate between QDRS global and Clinical Dementia Rating (CDR) Scale global scores is 70.66%. Memory item discrepancies primarily cause QDRS/CDR global score discordance. Cognitive scores are associated with QDRS/CDR concordances/discordances. Future analyses will explore QDRS relations to ADRD biomarkers.