Optimization of the APOP screener to predict functional decline or mortality in older emergency department patients: Cross-validation in four prospective cohorts

Introduction
Many screening instruments to predict adverse health outcomes in older patients visiting the emergency department (ED) have been developed, but successful implementation has been hampered because they are insufficiently validated or not tailored for the intended use of everyday clinical practice. The present study aims to refine and validate an existing screening instrument (the APOP screener) to predict 90-day functional decline or mortality in older ED patients.
Methods
Consecutive older patients (≥70 years) visiting the EDs of four hospitals were included and prospectively followed. First, an expert panel used predefined criteria to decide which independent predictors (including demographics, illness severity and geriatric parameters) were suitable for refinement of the model predicting functional decline or mortality after 90 days. Second, the model was cross-validated in all four hospitals and predictive performance was assessed. Additionally, a pilot study among triage nurses experiences and clinical usability of the APOP screener was conducted.
Results
In total 2629 older patients were included, with a median age of 79 years (IQR 74–84). After 90 days 805 patients (30.6%) experienced functional decline or mortality. The refined prediction model included age, gender, way of arrival, need of regular help, need help in bathing/showering, hospitalization the prior six months and impaired cognition. Calibration was good and cross-validation was successful with a pooled area under the curve of 0.71 (0.69–0.73). In the top 20% patients predicted to be at highest risk in total 58% (95%CI 54%–62%) experienced functional decline or mortality. Triage nurses found the screener well suited for clinical use, with room for improvement.
Conclusion
In conclusion, optimization of the APOP screener resulted in a short and more simplified screener, which adequately identifies older ED patients at highest risk for functional decline or mortality. The findings of the pilot study were promising for clinical use.