Table 2.

Univariate and multivariate analysis of factors associated with OS of patients in the training cohort

Variable	Variable level	Univariate analysis			Multivariate analysis
		HR	95%CI	p-value	HR	95%CI	p-value
Age	< 60	Reference			Reference
	≥60	1.517	1.370~1.680	< 0.001	1.328	1.198~1.471	< 0.001
Gender	Male	Reference					NI
	Female	0.968	0.888~1.056	0.470
Tumor Location in pancreas	Head	Reference			Reference
	Body	0.607	0.513~0.719	< 0.001	0.875	0.737~1.038	0.124
	Tail	0.507	0.438~0.588	< 0.001	0.737	0.634~0.857	< 0.001
Grade	Well	Reference			Reference
	Moderately	3.495	2.983~4.094	< 0.001	2.616	2.224~3.078	< 0.001
	Poorly	5.210	4.437~6.118	< 0.001	3.584	3.034~4.233	< 0.001
	Undifferentiated	4.274	3.001~6.086	< 0.001	3.385	2.371~4.832	< 0.001
AJCC TNM stage	I	Reference			Reference
	II	3.661	3.081~4.351	< 0.001	1.855	1.542~2.231	< 0.001
Regional lymph nodes surgery	None	Reference					NI
	1~3	1.477	0.600~3.638	0.396
	≥4	2.198	0.914~5.286	0.079
Tumor size (cm)	≤2	Reference			Reference
	(2~4)	1.960	1.715~2.240	< 0.001	1.303	1.136~1.494	< 0.001
	≥4	2.200	1.911~2.533	< 0.001	1.512	1.307~1.749	< 0.001
LNR	≤0.1732	Reference			Reference
	> 0.1732	1.991	1.821~2.176	< 0.001	1.522	1.388~1.669	< 0.001

Abbreviations: OS overall survival, AJCC American Joint Committee on Cancer, TNM Tumor-Node-Metastasis, LNR lymph node