Table 1. Patient characteristics.

Variable	Derivation Cohort (n = 100)	Validation Cohort (n = 148)
Female (%)	44	44
Age > 65 years (%)	61	59
Race A/B/C/H (%)	5/28/42/25	2/43/41/14
Low SES (%)	52	64
From ECF (%)	33	35
Hospital LOS (days ± SD)	12 ± 16	9 ± 10
Mortality (%)	36	30
Pneumonia (%)	62	64
Ischemia (%)	37	47
CRP > 10 (%)	47	49
High O2 requirement	44	39

Race: A: Asian, B: Black, C: Caucasian; H: Hispanic; ECF: extended care facility; LOS: length of stay; CRP = C-reactive protein; O2 = oxygen.