Table 2.

Electronic medical record features used to develop the model.

Feature group	Feature description (12-month clinical history from January 1, 2012-December 31, 2012)
Encounter history (n=40)	Visit counts of different encounter types (emergency/outpatient/inpatient/preadmission)
	The accumulated length of hospitalized stay
	Historical resource utilization
	Counts of historical chronic disease diagnoses
	Counts of total and no redundant total laboratory tests and outpatient prescriptions
Demographics (n=7)	Income, education, payer
	Age group was defined by age on January 1, 2013 (0, 1-5, 6-12, 13-18, 19-34, 35-49, 50-65, and ≥65 years)
Facility (n=8)	Different facilities
Diagnosis (n=14)	Counts for primary diagnosis and secondary diagnosis
Outpatient prescriptions (n=1)	Counts for different outpatient prescriptions