Which screening tool(s) should clinicians use for the detection of delirium in older, hospitalised patients?
Kirsty Hendry is a research assistant based at Glasgow Royal Infirmary having recently completed her PhD at the University of Glasgow. In this blog she discusses her recent Age and Ageing paper looking at screening of delirium in older, acute care in-patients. Kirsty can be contacted at Kirsty [dot] Hendry0 [at] gmail [dot] com
Delirium, suggested to be the most common psychiatric disorder suffered by older hospitalised individuals, has a low clinical awareness. This is despite existing guidelines such as those produced by the National Institute for Health and Care Excellence (NICE) and Healthcare Improvement Scotland (HIS) being in general agreement that delirium screening is important in older hospitalised patients.
There are a number of negative outcomes associated with delirium including increased risk of falls, dehydration, long-term cognitive impairment, institutionalisation and mortality. Identifying patients with delirium is essential to facilitate good patient care and to allow for the appropriate support of relatives and carers. There are a wide range of delirium screening tools available with limited validation of these tools within large, representative cohorts. MOTYB How do clinicians go about screening for delirium effectively?
We carried out an evaluation of cognitive screening tools recommended for routine clinical use in a consecutive cohort of patients >65 years old. The aim was to determine the feasibility and accuracy of these tools compared to a diagnosis of delirium using DSM 5 criteria. Screening tools evaluated were the Abbreviated Mental Test (AMT 4/AMT 10), the 4 A’s Test (4AT), the brief Confusion Assessment Method (bCAM) and the Single Question in Delirium (SQiD).
We found that the AMT 4, AMT 10 and 4AT were all feasible and accurate identifying over 86% of patients who received a clinician diagnosis of delirium. Months of the year backwards (MOTYB), which exists as a component of the 4AT and bCAM, was also found to be feasible and accurate as a standalone tool.
The bCAM was not found to be accurate within this cohort missing 3 in 10 patients diagnosed with delirium. The informant-based SQiD was found to be accurate, correctly identifying 91% of patients with delirium, but not feasible as a standalone tool with only 28% of relatives returning these forms to the nurse.
These results suggest that screening tools do exist which are accurate and quick to administer. The AMT 4 and MOTYB are particularly brief and require virtually no training to administer and score. We hope this study can help to inform existing clinical guidance and future research.
Read the Age & Ageing Paper 'Evaluation of delirium screening tools in geriatric medical inpatients: a diagnostic test accuracy study'