Pulling Back the Curtain on Hospital Dementia Detection: Validation of the Informant-Based Clinical Dementia Rating

Abstract

Background: Dementia often goes undetected in hospital settings, where cognitive assessments are challenging due to illness severity and delirium. This study aimed to (1) evaluate the accuracy of the Clinical Dementia Rating (CDR), based solely on knowledgeable informant reports, for detecting preexisting dementia and cognitive impairment in hospitalized patients compared to a gold-standard diagnosis, (2) and compare its performance to the 16-item Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE-16).

Methods: This cross-sectional study assessed consecutive patients aged ≥ 65 admitted to inpatient units from five hospitals in Brazil. The informant-based CDR was administered to knowledgeable informants within 48 h of admission, capturing patients' cognitive status 3 months before hospitalization to avoid the influence of acute cognitive impairments. Blinded experts provided a gold standard clinical diagnosis of dementia or cognitive impairment no dementia (CIND) based on a 90-min comprehensive assessment, including a standardized neuropsychology battery. Areas under the curve (AUC) examined diagnostic accuracy.

Results: Of 65 participants (mean age = 79.4 years; women = 54%), 34% had dementia and 32% had CIND. Compared to the gold standard, the informant-based CDR showed excellent diagnostic accuracy for detecting dementia (AUC = 0.92; 95% confidence interval [CI] = 0.86-0.98) and cognitive impairment (AUC = 0.93; 95% CI = 0.88-0.98), with a cutoff of ≥ 1 showing 98% specificity for dementia and a cutoff of ≥ 0.5 showing 98% sensitivity for cognitive impairment. Compared to the IQCODE-16, the informant-based CDR had similar performance in detecting dementia and a nonsignificant slight advantage in identifying cognitive impairment (AUC = 0.93 vs. 0.84, p = 0.069), reducing unrecognized cognitive impairment based on medical record documentation from 70% to 2%.

Conclusions: Informant-based CDR is a valid and efficient tool for detecting dementia and cognitive impairment in hospitalized older adults, supporting early diagnosis and guiding multidisciplinary interventions in acute care. Its use in routine hospitals may help clinicians reduce undetected cognitive impairment, enhance decision making, and improve patient care.

Keywords: acute disease; cognitive impairment; geriatric assessment; health care quality; triage.