Table 3.

Univariate and Multivariate Cox Regression Analysis for In-Hospital Mortality

	Training Cohort		Internal Validation Cohort		External Validation Cohort		External Validation Set 2
	HR (95% CI)	P value	HR (95% CI)	P value	HR (95% CI)	P value	HR (95% CI)	P value
Unadjusted	3.96 (2.44–6.41)	<0.001	3.26 (1.53–7.00)	0.002	1.91 (1.33–2.73)	<0.001	4.13 (1.09–15.59)	0.037
Model 1	3.93 (2.42–6.38)	<0.001	3.24 (1.51–6.93)	0.003	2.02 (1.41–2.90)	<0.001	4.52 (1.14–17.96)	0.032
Model 2	2.88 (1.76–4.72)	<0.001	3.47 (1.62–7.45)	0.001	1.96 (1.36–2.83)	<0.001	4.44 (1.10–21.02)	0.038
Model 3	2.64 (1.61–4.35)	<0.001	3.56 (1.66–7.66)	0.001	1.97 (1.35–2.88)	<0.001	4.16 (1.05–26.57)	0.044
Model 4	2.41 (1.44–4.03)	0.001	3.55 (1.60–7.87)	0.002	2.02 (1.37–2.97)	<0.001	3.27 (0.94–45.57)	NS

Notes: Model 1 adjusted for age, gender, body mass index, surgery type. Model 2 adjusted for model 1 plus comorbidities, drugs and interventions. Model 3 adjusted for Model 2 plus score system and Charlson index. Model 4 adjusted for model 3 plus laboratory results except for platelet and serum albumin.

Abbreviations: HR, hazard ratio; 95% CI, 95% confidence index; NS, not significant.