A practical method for predicting frequent use of emergency department care using routinely available electronic registration data

Abstract

Background: Accurately predicting future frequent emergency department (ED) utilization can support a case management approach and ultimately reduce health care costs. This study assesses the feasibility of using routinely collected registration data to predict future frequent ED visits.

Method: Using routinely collected registration data in the state of Indiana, U.S.A., from 2008, we developed multivariable logistic regression models to predict frequent ED visits in the subsequent two years. We assessed the model's accuracy using Receiver Operating Characteristic (ROC) curves, sensitivity, and positive predictive value (PPV).

Results: Strong predictors of frequent ED visits included age between 25 and 44 years, female gender, close proximity to the ED (less than 5 miles traveling distance), total visits in the baseline year, and respiratory and dental chief complaint syndromes. The area under ROC curve (AUC) ranged from 0.83 to 0.92 for models predicting patients with 8 or more visits to 16 or more visits in the subsequent two years, suggesting acceptable discrimination. With 25 % sensitivity, the model predicting frequent ED use as defined as 16 or more visits in 2009 and 2010 had a PPV of 59.5 % and specificity of 99.9 %. The "adjusted" PPV of this model, which includes patients having 8 or more visits, is 81.9 %.

Conclusion: We demonstrate a strong association between predictor variables present in registration data and frequent ED use. The algorithm's performance characteristics suggest that it is technically feasible to use routinely collected registration data to predict future frequent ED use.

Fig. 1

a. Distribution of patients stratified by year, 2008 to 2010; b. Emergency department utilization in 2009 and 2010 for patients with 4 or more visits in 2008; c. Emergency department utilization in 2009 and 2010 for patients with fewer visits less than 4 in 2008

Fig. 2

Equations for model predicting frequent emergency department (ED) use as defined as 8 or more visits (a) and model predicting frequent ED use as defined as 16 or more visits in the subsequent two years (b). Distance (<=5): the straight-line distances between geographic points from patients’ home to hospital less than 5 miles; Distance (>20): the straight-line distances between geographic points from patients’ home to hospital greater than 20 miles; CC: chief complaints; GI: gastrointestinal; RESP: respiratory; NEURO: neurological; UDI: undifferentiated infection; ILI: influenza-like illness and MUSC: musculoskeletal