Recalibration of the delirium prediction model for ICU patients (PRE-DELIRIC): a multinational observational study.

Purpose: Recalibration and determining discriminative power, internationally, of the existing delirium prediction model (PRE-DELIRIC) for intensive care patients.
Methods: A prospective multicenter cohort study was performed in eight intensive care units (ICUs) in six countries. The ten predictors (age, APACHE-II, urgent and admission category, infection, coma, sedation, morphine use, urea level, metabolic acidosis) were collected within 24 h after ICU admission. The confusion assessment method for the intensive care unit (CAM-ICU) was used to identify ICU delirium. CAM-ICU screening compliance and inter-rater reliability measurements were used to secure the quality of the data.
Results: A total of 2,852 adult ICU patients were screened of which 1,824 (64%) were eligible for the study. Main reasons for exclusion were length of stay <1 day (19.1%) and sustained coma (4.1%). CAM-ICU compliance was mean (SD) 82 ± 16% and inter-rater reliability 0.87 ± 0.17. The median delirium incidence was 22.5% (IQR 12.8-36.6%). Although the incidence of all ten predictors differed significantly between centers, the area under the receiver operating characteristic (AUROC) curve of the eight participating centers remained good: 0.77 (95% CI 0.74-0.79). The linear predictor and intercept of the prediction rule were adjusted and resulted in improved re-calibration of the PRE-DELIRIC model.
Conclusions: In this multinational study, we recalibrated the PRE-DELIRIC model. Despite differences in the incidence of predictors between the centers in the different countries, the performance of the PRE-DELIRIC-model remained good. Following validation of the PRE-DELIRIC model, it may facilitate implementation of strategies to prevent delirium and aid improvements in delirium management of ICU patients.