Validation of the 4AT tool for delirium assessment in specialist palliative care settings: protocol of a prospective diagnostic test accuracy study [version 1; peer review: 2 approved]

The 4AT, a rapid delirium detection tool for use in hospice inpatient units: Findings from a validation study

BACKGROUND

Delirium is a serious neuropsychiatric syndrome with adverse outcomes, which is common but often undiagnosed in terminally ill people. The 4 'A's test or 4AT (www.the4AT.com), a brief delirium detection tool, is widely used in general settings, but validation studies in terminally ill people are lacking.

AIM

To determine the diagnostic accuracy of the 4AT in detecting delirium in terminally ill people, who are hospice inpatients.

DESIGN

A diagnostic test accuracy study in which participants underwent the 4AT and a reference standard based on the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders. The reference standard was informed by Delirium Rating Scale Revised-98 and tests assessing arousal and attention. Assessments were conducted in random order by pairs of independent raters, blinded to the results of the other assessment.

SETTING/PARTICIPANTS

Two hospice inpatient units in Scotland, UK. Participants were 148 hospice inpatients aged ⩾18 years.

RESULTS

A total of 137 participants completed both assessments. Three participants had an indeterminate reference standard diagnosis and were excluded, yielding a final sample of 134. Mean age was 70.3 (SD = 10.6) years. About 33% (44/134) had reference standard delirium. The 4AT had a sensitivity of 89% (95% CI 79%-98%) and a specificity of 94% (95% CI 90%-99%). The area under the receiver operating characteristic curve was 0.97 (95% CI 0.94-1).

CONCLUSION

The results of this validation study support use of the 4AT as a delirium detection tool in hospice inpatients, and add to the literature evaluating methods of delirium detection in palliative care settings.

TRIAL REGISTRY

ISCRTN 97417474.

Exploration of delirium assessment and management in a hospice inpatient unit

Background: Delirium is common across all palliative care settings. Guidelines exist to support the care of terminally ill people who develop delirium; yet the evidence base is limited. Recent surveys of palliative care specialists have suggested clinical practice is variable. Aim: To explore delirium assessment and management in a hospice inpatient setting. Methods: A mixed-methods study comprising a retrospective case note review of 21 patients admitted to a hospice inpatient unit and semi-structured interviews with seven hospice inpatient doctors and nurses. Results: A total of 62% of patients were screened for delirium on admission using the 4 As tool (4AT). The period prevalence of delirium was 76% during the 2-week study period. The term ‘delirium’ was documented infrequently in case notes, compared to other more ambiguous terms. Interview data suggested that nurses were unfamiliar with delirium screening tools. Conclusion: Lack of awareness about delirium screening tools and the infrequent use of the term ‘delirium’ may suggest that delirium goes under-recognised and under-treated. Further education and research are required to support the care of terminally ill people with delirium.