Validation of the 4AT for Assessing Recovery from Delirium in Older Hospital Patients.

BACKGROUND:A crucial part of delirium care is assessing for recovery, yet there are no validated methods for this. The 4AT is a widely used delirium assessment tool, but its performance in assessing recovery remains unstudied. This study evaluated the 4AT's performance in assessing recovery from delirium. MATERIALS AND METHODS:In this prospective diagnostic accuracy study, older hospitalised patients (≥70 years) with reference standard delirium on enrolment were assessed 2-4 times over ≤9 days. Paired researchers independently conducted blinded assessments of (i) a reference standard (Diagnostic and Statistical Manual for Mental Disorders, 5th edition), including the Delirium Rating Scale-Revised-98 and neuropsychological tests and (ii) the 4AT (index test, score ≥ 4 positive) plus brief measures of distress and psychotic symptoms. RESULTS:A total of 120 people with delirium participated [median age 86.3, range 70-99, 67 (55.8%) female and 55 (45.8%) with dementia]. All of them completed the first two assessments, 103 (85.8%) completed three and 69 (57.5%) four. Reference standard delirium was present in 102/120 (85%), 72/103 (69.9%) and 53/69 (76.8%) cases at assessments two to four, respectively. In Receiver Operating Characteristic analyses, the 4AT's sensitivity for detecting delirium was 0.95 (confidence interval 0.91-0.99), 0.96 (0.91-1) and 0.94 (0.88-1), and specificity was 0.67 (0.13-1), 0.88 (0.71-1) and 1 (1-1) at assessments two to four. In total 18 (15%) participants recovered from delirium. Distress was common in delirium and decreased with recovery. CONCLUSION:The 4AT maintains diagnostic accuracy on repeated admissions and may effectively assess delirium recovery in acute hospital settings. Fewer patients than expected recovered within 9 days, suggesting more studies on the natural history of delirium in different settings would be informative.