Prediction of emergency department patient disposition based on natural language processing of triage notes

Background: : Nursing triage documentation is the first free-form text data created at the start of an emergency department (ED) visit. These 1-3 unstructured sentences reflect the clinical impression of an experienced nurse and are key in gauging a patient's illness. We aimed to predict final ED disposition using three commonly-employed natural language processing (NLP) techniques of nursing triage notes in isolation from other data. Methods: : We constructed a retrospective cohort of all 260,842 consecutive ED encounters in 2015-16, from three clinically heterogeneous academically-affiliated EDs. After exclusion of 3964 encounters based on completeness of triage, and disposition data, we included 256,878 encounters. We defined the outcome as: 1) admission, transfer, or in-ED death [68,092 encounters] vs. 2) discharge, "left without being seen," and "left against medical advice" [188,786 encounters]. The dataset was divided into training and testing subsets. Neural network regression models were trained using bag-of-words, paragraph vectors, and topic distributions to predict disposition and were evaluated using the testing dataset. Results: : Area under the curve for disposition using triage notes as bag-of-words, paragraph vectors, and topic distributions were 0.737 (95% CI: 0.734 - 0.740), 0.785 (95% CI: 0.782 - 0.788), and 0.687 (95% CI: 0.684 - 0.690), respectively. Conclusions: : Nursing triage notes can be used to predict final ED patient disposition, even when used separately from other clinical information. These findings have substantial implications for future studies, suggesting that free text from medical records may be considered as a critical predictor in research of patient outcomes.