Predicting adverse health outcomes in older emergency department patients: the APOP study

Background: Older patients experience high rates of adverse outcomes after an emergency department (ED) visit. Early identification of those at high risk could guide preventive interventions and tailored treatment decisions, but available models perform poorly in discriminating those at highest risk. The present study aims to develop and validate a prediction model for functional decline and mortality in older patients presenting to the ED. Methods: A prospective follow-up study in patients aged >= 70, attending the EDs of the LUMC, the Netherlands (derivation) and Alrijne Hospital, the Netherlands (validation) was conducted. A baseline assessment was performed and the main outcome, a composite of functional decline and mortality, was obtained after 90 days of follow-up. Results: In total 751 patients were enrolled in the Leiden University Medical Center of whom 230 patients (30.6%) experienced the composite outcome and 71 patients (9.5%) died. The final model for the composite outcome resulted in an area under the curve (AUC) of 0.73 (95% CI 0.67-0.77) and was experienced in 69% of the patients at highest risk. For mortality the AUC was 0.79 (95% CI 0.73-0.85) and 36% of the patients at highest risk died. External validation in 881 patients of Alrijne Hospital showed an AUC of 0.71 (95% CI 0.67-0.75) for the composite outcome and 0.67 (95% CI 0.60-0.73) for mortality. Conclusion: We successfully developed and validated prediction models for 90-day composite outcome and 90-day mortality in older emergency patients. The benefits for patient management by implementing these models with preventive interventions have to be investigated.