Table 4.

Discrimination and calibration of APACHE II before and after customization for various subgroups of the validation sample

Subgroup	Prediction	n	ROC area	H	C	SMR (95% CI)
Medical	Original	615	0.842	5.89	12.08	1.08 (0.94-1.23)
	Customized		0.842	7.90	9.65	1.01 (0.88-1.15)
Surgical	Original	317	0.758	5.48	7.15	0.91 (0.65-1.18)
	Customized		0.758	6.87	7.53	0.86 (0.60-1.11)
< 65 years	Original	485	0.859	14.31	20.13†	0.91 (0.70-1.13)
	Customized		0.859	8.82	19.90*	0.86 (0.66-1.07)
≥ 65 years	Original	447	0.774	8.09	8.31	1.11 (0.96-1.27)
	Customized		0.774	7.16	7.27	1.04 (0.89-1.19)
Direct admission	Original	635	0.816	12.12	16.01*	0.99 (0.82-1.10)
	Customized		0.816	7.98	15.57*	0.93 (0.77-1.10)
Transferral	Original	297	0.814	3.05	3.90	1.10 (0.87-1.23)
	Customized		0.814	7.06	2.74	1.03 (0.85-1.20)
Cardiovascular	Original	360	0.879	9.21	11.13	1.05 (0.86-1.24)
	Customized		0.879	10.44	8.83	0.99 (0.80-1.17)
Gastrointestinal	Original	296	0.855	11.12	12.82	0.76 (0.53-0.98)
	Customized		0.855	12.31	13.73	0.71 (0.49-0.92)

Direct admission is defined as admission from emergency room, operating theatre, or recovery room; and transferral is defined as admission from other hospital, other ICU, or floor. C, Hosmer-Lemeshow goodness-of-fit C test; H, Hosmer-Lemeshow goodness-of-fit H test; CI, confidence interval. ^*P < 0.05, ^†P = 0.01.