Diagnostic accuracy of the 4AT for delirium detection in older adults: 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 minutes) 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 (≥65 years); 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 Seventeen studies (3,702 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. PROSPERO Registration number CRD42019133702.

Factors for a Timely Identification of Possible Occurrence of Delirium in Palliative Care: A Prospective Observational Study

“…During this period, attention was paid on recognizing patients who developed delirium and those who did not develop it. The diagnosis of delirium was carried out by means of 4AT, a frequently adopted tool for rapid delirium screening [19][20][21].…”

Validation of the 4AT tool for delirium assessment in specialist palliative care settings: protocol of a prospective diagnostic test accuracy study

“…Use of the SQiD is limited when an informant is unavailable. 40 . The 4AT's advantages over other tools are that no special training is required prior to use, and it is quick and easy to administer.…”

“…A recent meta-analysis of 17 studies on the diagnostic accuracy of the 4AT in a variety of clinical settings, reported a pooled sensitivity of 0.88 (95% CI 0.80-0.93) and a pooled specificity of 0.88 (95% CI 0.82-0.92) 40 . In line with guidance described by Flahault et al (2005) 44 which suggests a sample size of 176, given a sensitivity/specificity of 0.85, and a minimal acceptable lower confidence level of 0.75, we plan to recruit 240 patients from the inpatient units across both hospices.…”

Postoperative Delirium

“…56 Validated screening tools with reasonable psychometric properties include the short form of the Confusion Assessment Method (CAM) (positive likelihood ratio [LR] = 9.6; 95% CI: 5.8-16.0 and negative LR = 0.16; 95% CI: 0.09-0.29) and the 4 "A"s Test (4AT) (sensitivity = 87%; 95% CI: 77-93, and specificity = 83%; 95% CI: 73-89). 57,58 In Canada, the most commonly used screening tool is the short form of the CAM which is based on the presence of four core features of delirium: acute onset and fluctuating course of symptoms, inattention, and either disorganized thinking or altered level of consciousness. 59 The CAM requires specific training in rating each of the features, including formal testing of attention, and must incorporate history from informants plus review of medical records.…”