Table 5. Any adverse outcome or unplanned readmission model performance with sequential addition of variable groups and measures of prediction increment.

Variable	No. of data elements	C−statistic (%)	Event NRI (>0) (%)	Nonevent NRI (>0) (%)	Combined NRI (>0)	P value, HL test
Severe adverse event-models§ (derivation cohort)
Age	1	0.54	–	–	–	0.87
+ Gender	2	0.55	15	−11	0.04	0.29
+ ASA class 3/4	3	0.58	23	6	0.29	0.79
+ Intraoperative variables	4	0.63	1	30	0.31	0.12
+ Laboratory values	12	0.66	−26	54	0.28	0.97
+ Comorbid conditions (full model)	16	0.66	−33	53	0.20	0.78
Severe adverse event-models§ (validation cohort)
Age	1	0.57	–	–	–	0.06
+ Gender	2	0.58	12	−8	0.04	0.20
+ ASA class 3/4	3	0.61	32	1	0.33	0.24
+ Intraoperative variables	4	0.65	2	29	0.31	0.20
+ Laboratory values	12	0.68	−29	59	0.30	0.06
+ Comorbid conditions (full model)	16	0.69	−24	53	0.29	0.62
Unplanned readmission-models§ (derivation cohort)
Age	1	0.54	–	–	–	0.86
+ Gender	–	–	–	–	–	–
+ ASA class 3/4	2	0.57	17	5	0.22	0.85
+ Intraoperative variables	3	0.58	−12	23	0.11	0.06
+ Laboratory values	9	0.61	−29	52	0.23	0.98
+ Comorbid conditions (full model)	13	0.62	−29	43	0.14	0.77
Unplanned readmission-models§ (validation cohort)
Age	1	0.59	–	–	–	0.10
+ Gender	–	–	–	–	–	–
+ ASA class 3/4	2	0.62	33	0	0.33	0.85
+ Intraoperative variables	3	0.62	−10	20	0.10	0.49
+ Laboratory values	9	0.64	−38	58	0.20	0.30
+ Comorbid conditions (full model)	13	0.65	−47	68	0.21	0.58

^§, as groups of variables were sequentially added. A P value of >0.05 for the Hosmer-Lemeshow goodness-of-fit test demonstrates good model calibration; a P value of <0.05 for the Hosemer-Lemeshow goodness-of-fit test suggests a poor model fit.