Diagnostic accuracy of the 4AT for delirium detection: systematic review and meta-analysis

Abstract

Objective: Detection of delirium in hospitalised older adults is recommended in national and international guidelines. The 4 'A's Test (4AT) is a short (<2 min) instrument for delirium detection that is used internationally as a standard tool in clinical practice. We performed a systematic review and meta-analysis of diagnostic test accuracy of the 4AT for delirium detection. Methods: We searched MEDLINE, EMBASE, PsycINFO, CINAHL, clinicaltrials.gov and the Cochrane Central Register of Controlled Trials, from 2011 (year of 4AT release on the website www.the4AT.com) until 21 December 2019. Inclusion criteria were: older adults (≥65y); diagnostic accuracy study of the 4AT index test when compared to delirium reference standard (standard diagnostic criteria or validated tool). Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Pooled estimates of sensitivity and specificity were generated from a bivariate random effects model. Results: 17 studies (3702 observations) were included. Settings were acute medicine, surgery, a care home, and the emergency department. Three studies assessed performance of the 4AT in stroke. The overall prevalence of delirium was 24.2% (95% CI 17.8-32.1%; range 10.5-61.9%). The pooled sensitivity was 0.88 (95% CI 0.80-0.93) and the pooled specificity was 0.88 (95% CI 0.82-0.92). Excluding the stroke studies, the pooled sensitivity was 0.86 (95% CI 0.77-0.92) and the pooled specificity was 0.89 (95% CI 0.83-0.93). The methodological quality of studies varied but was moderate to good overall. Conclusions: The 4AT shows good diagnostic test accuracy for delirium in the 17 available studies. These findings support its use in routine clinical practice in delirium detection.

Delirium

“…The four items are alertness, cognition (a short test of orientation), attention (recitation of the months in backwards order), and the presence of acute change or fluctuating course. A meta-analysis of 17 diagnostic test accuracy studies (n = 3,701 observations) reported a pooled sensitivity and specificity of 88% 217 . In a randomized controlled trial, the 4AT had higher sensitivity than and similar specificity to the CAM 208 .…”

Care for Older People with Dementia During COVID-19 Pandemic

“…A rapid screening tool for delirium is the 4 AT which may take only 2 min to do. The 4AT is a well-validated tool that shows good diagnostic accuracy with a pooled sensitivity of 0.88 (95% CI 0.80 to 0.93) and pooled specificity of 0.88 (95% CI 0.82 to 0.92) in older (≥ 65 years) people in various care settings that include emergency department, medical, stroke and surgical wards [18]. Precipitating factors for delirium such as sleep deprivation, pain, constipation and urinary retention should be avoided or promptly treated as possible.…”

Delirium in Older People with COVID-19: Clinical Scenario and Literature Review

“…88 (95% CI 0.80 to 0.93) and pooled specificity of 0.88 (95% CI 0.82 to 0.92) in older (≥ 65 years) people in various care settings that include emergency department, medical, stroke and surgical wards. [24] The 4AT has some advantages over other screening tools such as the Acute Confusion Method (CAM) as being shorter, simpler and not requiring special training for the operator. [24] The 4AT is designed to be used by any health care professional at the first contact with patient and at follow-up at any time when delirium is suspected (Table 3).…”