Evaluating the Accuracy and Reliability of Telephone-Derived Clinical Dementia Rating Scores: A Comparative Analysis with In-Person Assessments

INTRODUCTION:The Clinical Dementia Rating (CDR) scale typically is administered in person, but use of telephone-based, informant-only assessments increased during the coronavirus disease 2019 (COVID-19) pandemic. The correspondence of informant-only assessments with in-person ratings remains unclear. METHODS:We analyzed 1,140 paired in-person and telephone assessments from the Knight Alzheimer's Disease Research Center Memory and Aging Project conducted within 12 months. Agreement for global CDR and CDR Sum of Boxes (CDR-SB) was examined using kappa statistics, intraclass correlation coefficients (ICCs), and Bland-Altman methods; classification performance of telephone global CDR score ≥ 0.5 was assessed. RESULTS:Agreement for the global CDR was moderate (κ = 0.53, 95% CI: 0.47-0.59). CDR-SB demonstrated moderate reliability (ICC = 0.69, 95% confidence interval [CI]: 0.65-0.73). Telephone CDR-SB scores averaged 0.40 points higher than in-person scores, with wide limits of agreement. Sensitivity was 64.2% and specificity 91.9%. DISCUSSION:Telephone CDR-SB shows moderate concordance with in-person CDR-SB but shows consistent score inflation, which may limit clinical staging utility.