Table 3.

Subset of Features Used in the Training of Regression Models (full feature set described in the Appendix)

Data Source Combinations for Training (total number of features in this category)	Example Features (Full list in Appendix)
Demographics (8)	Age (years); Gender; Ethnicity Codes; Visit History in the Preceding Year
Visit History (4)	# of thirty-day readmissions x 1 year # of inpatient admissions x 1 year # of outpatient visits x 1 year # of emergency room visits x 1 year
Laboratory Tests (100)	Hemoglobin; Blood Urea Nitrogen; Creatinine; Troponin; Blood Glucose
Prior ICD9 Codes (48)	Congestive Heart Failure; Diabetes Mellitus; Stroke; Dementia; Cirrhosis; Chronic Kidney Disease; Pain Syndrome
Social and Mental Health/Behavioral Factors (40)	Refuse(al,ing,ed); Homeless; Depress(ed/ion); Abuse; Dependence; Withdrawal
Other Keywords (52)	Fluid; Coumadin (warfarin); ESRD; Dialysis; Obes(e,ity); Frail(ty); Sep(sis/tic); Hemorrhag(e/ic)