Calibration of the PREdiction of DELIRium in ICu Patients (PRE-DELIRIC) Score in a Cohort of Critically Ill Patients: A Retrospective Cohort Study

BACKGROUND: To predict delirium in intensive care unit (ICU) patients, the Prediction of Delirium in ICU Patients (PRE-DELIRIC) score may be used. This model may help nurses to predict delirium in high-risk ICU patients. OBJECTIVES: The aims of this study were to externally validate the PRE-DELIRIC model and to identify predictive factors and outcomes for ICU delirium. METHOD: All patients underwent delirium risk assessment by the PRE-DELIRIC model at admission. We used the Intensive Care Delirium Screening Check List to identify patients with delirium. The receiver operating characteristic curve measured discrimination capacity among patients with or without ICU delirium. Calibration ability was determined by slope and intercept. RESULTS: The prevalence of ICU delirium was 55.8%. Discrimination capacity (Intensive Care Delirium Screening Check List score ≥4) expressed by the area under the receiver operating characteristic curve was 0.81 (95% confidence interval, 0.75-0.88), whereas sensitivity was 91.3% and specificity was 64.4%. The best cut-off was 27%, obtained by the max Youden index. Calibration of the model was adequate, with a slope of 1.03 and intercept of 8.14. The onset of ICU delirium was associated with an increase in ICU length of stay (P < .0001), higher ICU mortality (P = .008), increased duration of mechanical ventilation (P < .0001), and more prolonged respiratory weaning (P < .0001) compared with patients without delirium. DISCUSSION: The PRE-DELIRIC score is a sensitive measure that may be useful in early detection of patients at high risk for developing delirium. The baseline PRE-DELIRIC score could be useful to trigger use of standardized protocols, including nonpharmacologic interventions.