Nonelective Rehospitalizations and Postdischarge Mortality: Predictive Models Suitable for Use in Real Time

Hospital discharge planning has been hampered by the lack of predictive models. OBJECTIVE: To develop predictive models for nonelective rehospitalization and postdischarge mortality suitable for use in commercially available electronic medical records (EMRs). DESIGN: Retrospective cohort study using split validation. SETTING: Integrated health care delivery system serving 3.9 million members. PARTICIPANTS: A total of 360,036 surviving adults who experienced 609,393 overnight hospitalizations at 21 hospitals between June 1, 2010 and December 31, 2013. MAIN OUTCOME MEASURE: A composite outcome (nonelective rehospitalization and/or death within 7 or 30 days of discharge). RESULTS: Nonelective rehospitalization rates at 7 and 30 days were 5.8% and 12.4%; mortality rates were 1.3% and 3.7%; and composite outcome rates were 6.3% and 14.9%, respectively. Using data from a comprehensive EMR, we developed 4 models that can generate risk estimates for risk of the combined outcome within 7 or 30 days, either at the time of admission or at 8 am on the day of discharge. The best was the 30-day discharge day model, which had a c-statistic of 0.756 (95% confidence interval, 0.754–0.756) and a Nagelkerke pseudo-R(2) of 0.174 (0.171–0.178) in the validation dataset. The most important predictors—a composite acute physiology score and end of life care directives—accounted for 54% of the predictive ability of the 30-day model. Incorporation of diagnoses (not reliably available for real-time use) did not improve model performance. CONCLUSIONS: It is possible to develop robust predictive models, suitable for use in real time with commercially available EMRs, for nonelective rehospitalization and postdischarge mortality.