Table 4. Area under the receiver operating characteristics curve (95% Confidence Interval) of predicted probabilities by hospital mortality of each PIRO component, the combined PIRO model and SAPS II, in the derivation and in the validation cohorts.

	Predisposition	Insult	Response	Organ	PIRO	SAPS II
Study population (n = 1035)	0.79 (0.75–0.83)	0.59 (0.54–0.64)	0.72 (0.67–0.77)	0.71 (0.66–0.75)	0.85 (0.82–0.88)	0.81 (0.77–0.84)
Ward (n = 886)	0.84 (0.80–0.88)	0.61 (0.55–0.67)	0.66 (0.60–0.72)	0.66 (0.60–0.72)	0.84 (0.80–0.88)	0.78 (0.74–0.83)
ICU (n = 149)	0.77 (0.69–0.86)	0.50 (0.40–0.60)	0.79 (0.71–0.88)	0.70 (0.61–0.79)	0.83 (0.75–0.91)	0.83 (0.76–0.91)
Validation cohort (n = 186)	0.75 (0.67–0.83)	0.60 (0.49–0.70)	0.73 (0.64–0.83)	0.77 (0.69–0.85)	0.84 (0.76–0.91)	0.85 (0.78–0.92)