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Lookup NU author(s): Dr Sarah Richardson
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© The Author(s) 2026. Published by Oxford University Press on behalf of the British Geriatrics Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Presenting features of delirium can be difficult to distinguish from co-existing dementia phenomenology. While the 4 ‘A’s Test (4AT) is a well validated delirium screening tool across multiple patient populations and healthcare settings, how its diagnostic performance varies across different levels of baseline cognition is unclear. Methods: This study harmonises data from two prospective cohorts: the Delirium and Population Health Informatics Cohort (DELPHIC) and Delirium and Cognitive Impact in Dementia (DECIDE). Both cohorts were stratified into tertiles according to baseline cognition. Delirium was defined using DSM-IV (DELPHIC) and DSM-V (DECIDE). 4AT domain scores were operationalised from relevant delirium assessments within each study (MDAS, OSLA, months of the year backwards); item 4 was drawn from assessments of fluctuation. This process yielded an operationalised 4AT. Diagnostic accuracy of the operationalised 4AT was calculated using sensitivity, specificity, and receiver operating characteristics, with pooled estimates for each test domain. Results: Among 396 unique participants and 2468 assessments across both studies, pooled 4AT sensitivity and specificity were 0.73 and 0.89, respectively. Overall 4AT performance was consistent across cognitive tertiles (sensitivity: high 0.82, middle 0.73, low 0.71; specificity: high 0.91; middle 0.92; low 0.86). Conclusions: The operationalised 4AT showed good diagnostic performance in all three levels of baseline cognition. Sensitivity would likely have been higher had clinical information to inform 4AT item 4 been available. Overall, however, the findings support the value of bedside 4AT items in detecting delirium in hospitalised patients across the spectrum of baseline cognition.
Author(s): Hogan P, Cheston H, Dunne O, Gardner D, McWhirter A, Rawle MJ, Stoodley I, Richardson SJ, Allan LM, MacLullich AMJ, Davis DHJ, Tsui A
Publication type: Article
Publication status: Published
Journal: Age and Ageing
Year: 2026
Volume: 55
Issue: 6
Online publication date: 11/05/2026
Acceptance date: 24/06/2026
Date deposited: 13/07/2026
ISSN (print): 0002-0729
ISSN (electronic): 1468-2834
Publisher: Oxford University Press
URL: https://doi.org/10.1093/ageing/afag182
DOI: 10.1093/ageing/afag182
Data Access Statement: Complete deidentified participant data, along with study protocols, consent forms, and case report forms are available through the Dementias Platform UK Data Portal: https://portal.dementiasplatform.uk/.
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