Development and validation of a delirium predictive score in older people

Background: delirium is frequently under diagnosed in older hospitalised patients. Predictive models have not been widely incorporated in clinical practice. Objective: to develop and validate a predictive score for incident delirium. Design and setting: two consecutive observational prospective cohorts (development and validation) in a university affiliated hospital. Subjects: inpatients 65 years and older. Methods: in the development cohort patients were assessed within the first 48 h of admission, and every 48 h thereafter, using the confusion assessment method to diagnose delirium and data were collected on comorbidity, illness severity, function-al status and laboratory. Delirium predictive score (DPS) was constructed in the development cohort using variables associated with incident delirium in the multivariate analysis (P < 0.05), and then tested in a validation cohort of comparable patients, ad-mitted without delirium. Receiver operating characteristic (ROC) analysis and likelihood ratio (LR) were calculated. Results: the development cohort included 374 patients, incident delirium occurred in 25. After multivariate analysis incident delirium was independently associated with lower functional status (Barthel Index) and a proxy for dehydration (elevated urea to creatinine ratio). Using these variables, DPS was constructed with a performance in the ROC curve area of 0.86 (95 % CI