BMJ Open -
This study aimed to test the performance of new variants of models to identify people at risk of an emergency hospital admission. It compared the impact of using alternative data sources (hospital inpatient, A&E, outpatient and GP electronic medical records; the effects of local calibration on the performance of the models; and the choice of population denominators. It found that the addition of more detailed data sets led to moderate improvement in the number of patients identified; the use of general practitioner registry data for the denominator proved to be of significant importance; and that models calibrated to local data sets did not show consistent improvement over models built on pooled data.