Predicting delirium after hip fracture with a 2-min cognitive screen: prospective cohort study

Background: although the importance of identifying hip fracture patients with high risk for delirium has been well established, considerable controversy exists over the choice of the screening tool. The most commonly used cognitive screeners take an excessive amount of time and include drawing tasks that can be troublesome for individuals with hip fracture who are invariably lying in bed.

Objective: to evaluate the properties of the 10-point Cognitive Screener (10-CS), a 2-min bedside tool, for predicting delirium in older adults with hip fracture.

Design: prospective cohort study.

Setting: a tertiary referral hospital in São Paulo, Brazil.

Subjects: non-delirious older adults with hip fracture (n = 147).

Methods: the 10-CS was administered as a baseline predictor. The test is composed of three-item temporal orientation (date, month, year), category fluency (animals in 1 min) and three-word recall. Incident delirium has been diagnosed according to the Confusion Assessment Method (CAM) that was administered daily from admission to discharge.

Results: during hospitalisation, 61 (41.5%) patients developed delirium. The 10-CS presented excellent accuracy for predicting delirium, with an area under ROC curve of 0.83 (95% CI 0.76-0.89). After adjusting for demographic and clinical variables, participants with probable cognitive impairment (score ≤ 5) were more likely to develop delirium (HR = 7.48; 95% CI 2.2-25.4) compared with participants with a normal score. Lower scores on the 10-CS were also independently associated with a longer length of stay.

Conclusions: the 10-CS is an easy-to-use bedside tool with adequate properties to stratify the risk of delirium in older adults with hip fracture.