Predicting and validating 30-day hospital readmission in adults with diabetes whose index admission is diabetes-related.

OBJECTIVE: The primary objective is to develop a prediction model of 30-day hospital readmission amongst adults with diabetes mellitus (DM) whose index admission was DM-related. The secondary aims are to: internally and externally validate the prediction model; and compare its performance with two existing models.

RESEARCH DESIGN AND SETTING: Data of inpatients aged ≥18 years from 2008-2015 were extracted from the electronic medical record system of the National University Hospital, Singapore. Unplanned readmission within 30 days was calculated from the discharge date of the index hospitalisation. Multivariable logistic regression and 10-fold cross-validation were performed. For external validation, simulations based on prevalence of 30-day readmission and the regression coefficients provided by referenced papers were conducted.

RESULTS: 11.0% of 2355 patients reported 30-day readmission. The prediction model included four predictors: length of stay, ischaemic heart disease, peripheral vascular disease and number of drugs. C-statistics for the prediction model and 10-fold cross-validation were 0.68 (95% CI: 0.66, 0.70) and 0.67 (95% CI: 0.63 to 0.70) respectively. Those for the three simulated external validation datasets ranged from 0.64 to 0.68.

CONCLUSION: The prediction model performs well with good internal and external validity for identifying patients with DM at risk of unplanned 30-day readmission.