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.

Blue spaces have been found to have significant salutogenic effects. However, little is known about the mechanisms and pathways that link blue spaces and health. The purpose of this systematic review and meta-analysis is to summarise the evidence and quantify the effect of blue spaces on four hypothesised mediating pathways: physical activity, restoration, social interaction and environmental factors. Following the PRISMA guidelines, a literature search was conducted using six databases (PubMed, Scopus, PsycInfo, Web of Science, Cochrane Library, EBSCOHOST/CINAHL). Fifty studies were included in our systematic review. The overall quality of the included articles, evaluated with the Qualsyst tool, was judged to be very good, as no mediating pathway had an average article quality lower than 70%. Random-effects meta-analyses were conducted for physical activity, restoration and social interaction. Living closer to blue space was associated with statistically significantly higher physical activity levels (Cohen’s d = 0.122, 95% CI: 0.065, 0.179). Shorter distance to blue space was not associated with restoration (Cohen’s d = 0.123, 95% CI: −0.037, 0.284) or social interaction (Cohen’s d = −0.214, 95% CI: −0.55, 0.122). Larger amounts of blue space within a geographical area were significantly associated with higher physical activity levels (Cohen’s d = 0.144, 95% CI: 0.024, 0.264) and higher levels of restoration (Cohen’s d = 0.339, 95% CI: 0.072, 0.606). Being in more contact with blue space was significantly associated with higher levels of restoration (Cohen’s d = 0.191, 95% CI: 0.084, 0.298). There is also evidence that blue spaces improve environmental factors, but more studies are necessary for meta-analyses to be conducted. Evidence is conflicting on the mediating effects of social interaction and further research is required on this hypothesised pathway. Blue spaces may offer part of a solution to public health concerns faced by growing global urban populations.

Delirium affects > 15% of hospitalised patients but is grossly underdetected, contributing to poor care. The 4 ‘A’s Test (4AT, www.the4AT.com ) is a short delirium assessment tool designed for routine use without special training. The primary objective was to assess the accuracy of the 4AT for delirium detection. The secondary objective was to compare the 4AT with another commonly used delirium assessment tool, the Confusion Assessment Method (CAM). This was a prospective diagnostic test accuracy study set in emergency departments or acute medical wards involving acute medical patients aged ≥ 70. All those without acutely life-threatening illness or coma were eligible. Patients underwent (1) reference standard delirium assessment based on DSM-IV criteria and (2) were randomised to either the index test (4AT, scores 0–12; prespecified score of > 3 considered positive) or the comparator (CAM; scored positive or negative), in a random order, using computer-generated pseudo-random numbers, stratified by study site, with block allocation. Reference standard and 4AT or CAM assessments were performed by pairs of independent raters blinded to the results of the other assessment. Eight hundred forty-three individuals were randomised: 21 withdrew, 3 lost contact, 32 indeterminate diagnosis, 2 missing outcome, and 785 were included in the analysis. Mean age was 81.4 (SD 6.4) years. 12.1% (95/785) had delirium by reference standard assessment, 14.3% (56/392) by 4AT, and 4.7% (18/384) by CAM. The 4AT had an area under the receiver operating characteristic curve of 0.90 (95% CI 0.84–0.96). The 4AT had a sensitivity of 76% (95% CI 61–87%) and a specificity of 94% (95% CI 92–97%). The CAM had a sensitivity of 40% (95% CI 26–57%) and a specificity of 100% (95% CI 98–100%). The 4AT is a short, pragmatic tool which can help improving detection rates of delirium in routine clinical care. International standard randomised controlled trial number (ISRCTN) 53388093 . Date applied 30/05/2014; date assigned 02/06/2014.

Background: Delirium is a common and serious neuropsychiatric syndrome, usually triggered by illness or drugs. It remains underdetected. One reason for this is a lack of brief, pragmatic assessment tools. The 4 ‘A’s test (Arousal, Attention, Abbreviated Mental Test – 4, Acute change) (4AT) is a screening tool designed for routine use. This project evaluated its usability, diagnostic accuracy and cost.Methods: Phase 1 – the usability of the 4AT in routine practice was measured with two surveys and two qualitative studies of health-care professionals, and a review of current clinical use of the 4AT as well as its presence in guidelines and reports. Phase 2 – the 4AT’s diagnostic accuracy was assessed in newly admitted acute medical patients aged ≥ 70 years. Its performance was compared with that of the Confusion Assessment Method (CAM; a longer screening tool). The performance of individual 4AT test items was related to cognitive status, length of stay, new institutionalisation, mortality at 12 weeks and outcomes. The method used was a prospective, double-blind diagnostic test accuracy study in emergency departments or in acute general medical wards in three UK sites. Each patient underwent a reference standard delirium assessment and was also randomised to receive an assessment with either the 4AT (n = 421) or the CAM (n = 420). A health economics analysis was also conducted.Results: Phase 1 found evidence that delirium awareness is increasing, but also that there is a need for education on delirium in general and on the 4AT in particular. Most users reported that the 4AT was useful, and it was in widespread use both in the UK and beyond. No changes to the 4AT were considered necessary. Phase 2 involved 785 individuals who had data for analysis; their mean age was 81.4 (standard deviation 6.4) years, 45% were male, 99% were white and 9% had a known dementia diagnosis. The 4AT (n = 392) had an area under the receiver operating characteristic curve of 0.90. A positive 4AT score (> 3) had a specificity of 95% [95% confidence interval (CI) 92% to 97%] and a sensitivity of 76% (95% CI 61% to 87%) for reference standard delirium. The CAM (n = 382) had a specificity of 100% (95% CI 98% to 100%) and a sensitivity of 40% (95% CI 26% to 57%) in the subset of participants whom it was possible to assess using this. Patients with positive 4AT scores had longer lengths of stay (median 5 days, interquartile range 2.0–14.0 days) than did those with negative 4AT scores (median 2 days, interquartile range 1.0–6.0 days), and they had a higher 12-week mortality rate (16.1% and 9.2%, respectively). The estimated 12-week costs of an initial inpatient stay for patients with delirium were more than double the costs of an inpatient stay for patients without delirium (e.g. in Scotland, £7559, 95% CI £7362 to £7755, vs. £4215, 95% CI £4175 to £4254). The estimated cost of false-positive cases was £4653, of false-negative cases was £8956, and of a missed diagnosis was £2067.Limitations: Patients were aged ≥ 70 years and were assessed soon after they were admitted, limiting generalisability. The treatment of patients in accordance with reference standard diagnosis limited the ability to assess comparative cost-effectiveness.Conclusions: These findings support the use of the 4AT as a rapid delirium assessment instrument. The 4AT has acceptable diagnostic accuracy for acute older patients aged > 70 years.Future work: Further research should address the real-world implementation of delirium assessment. The 4AT should be tested in other populations.Trial registration: Current Controlled Trials ISRCTN53388093.Funding: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full inHealth Technology Assessment; Vol. 23, No. 40. See the NIHR Journals Library website for further project information. The funder specified that any new delirium assessment tool should be compared against the CAM, but had no other role in the study design or conduct of the study.