Table 3 Univariate and multivariate Cox regression models before matching

Gender (F vs. M)

0.84(0.68,1.03)

0.1

Age

1.01(1,1.02)

0.06

Body mass index

0.99(0.96,1.02)

0.49

ASA score

 1

reference

 2

1.02(0.6,1.72)

0.95

 3

1.33(0.76,2.32)

0.32

Surgical method

 Whipple

 Distal pancreatectomy

1.08(0.87,1.33)

0.47

 Other

0.81(0.33,1.98)

0.65

Spleen resection (Y vs. N)

1.05(0.85,1.29)

0.67

Site of tumor (Head vs. Body/Tail)

1.1(0.89,1.36)

0.36

Size of tumor

1.1(1.04,1.16)

< 0.01

1.11(1.05,1.18)

< 0.01

Lymph node metastasis (Y vs. N)

1.39(1.25,1.51)

< 0.01

1.32(1.15,1.45)

< 0.01

Differentiation

 Poor

reference

reference

 Moderate

0.79(0.59,1.07)

0.13

0.9(0.66,1.22)

0.5

 Well

0.51(0.34,0.76)

< 0.01

0.65(0.43,0.98)

0.04

Surgical margin (R1 vs. R0)

1.87(1.15,3.05)

0.01

1.74(1.06,2.86)

0.03

Lymphovascular invasion (Y vs. N)

1.17(0.92,1.48)

0.2

Neural invasion (Y vs. N)

1.11(0.88,1.39)

0.39

Capsule invasion (Y vs. N)

1.48(1.15,1.91)

< 0.01

1.32(1.01,1.74)

0.04

Bile duct invasion (Y vs. N)

1.12(0.89,1.4)

0.32

Duodenal invasion (Y vs. N)

1.25(0.99,1.59)

0.06

Spleen invasion (Y vs. N)

1.68(1.2,2.36)

< 0.01

1.18(0.83,1.68)

0.35

SPS (+ vs. -)

1.86(1.4,2.48)

< 0.01

1.98(1.48,2.64)

< 0.01