The relationship among frailty, delirium and attentional tests to detect delirium: a cohort study

Background Few studies explored if frailty predisposes to delirium in hospitalized older patients. The aims of this study were to evaluate if frailty: 1) is independently associated with delirium, and 2) affects the patient's performance in three tests of attention used to detect delirium. Methods Data are from a prospective cohort study of patients admitted to an Acute Geriatric Unit (AGU). Frailty was operationalized using the health deficit accumulation model (38-item Frailty Index). Delirium was screened using the 4AT, and the diagnosis confirmed with the DSM-5th criteria. During the first 7 days from the hospital admission, patients also underwent a double-blind assessment of attention using three ad hoc tests (i.e., Months of the year backwards, MOTYB; Days of the week backwards, DOWB; and Count backwards from 20 to 1, CB). Results Eighty-nine patients were included (mean age 83.1 years, standard deviation 6.0). Forty-two (47.19%) patients were frail, and 37 (41.7%) had delirium. The likelihood of delirium was significantly higher in frail compared to the non-frail patients; it was also inversely associated with the three attention tests. Using the MOTYB test, the ability to discriminate delirium was similar in patients with (Area Under the Receiving Operator Characteristic [AUROC] 0.88, 95% Confidence Interval [CI] 0.82-0.92) and without frailty (AUROC 0.93, 95%CI 0.90-0.95) whilst was markedly different between the same groups using either DOWB and CB. Conclusions Frailty is associated with delirium in hospitalized older patients and can influence the patient's performances at attentional tests that are commonly used to screen delirium.