Table 1 Baseline characteristics of surgeries in validation and development cohort

n

225

96

250

Age (years), median [IQR]

66

[55–75]

68

[58–75]

65

[52–73]

Female sex, n (%)

110

(48.9)

37

(38.5)

92

(36.8)

BMI, median [IQR]

25.6

[22.3–29.4]

25.7

[22.3–29.7]

25.2

[22.6–28.6]

- Missing, n (%)

2

(0.9)

1

(1.0)

0

(0.0)

ASA classification, n (%)

- Grade I

25

(11.1)

9

(9.4)

17

(6.8)

- Grade II

96

(42.7)

35

(36.5)

125

(50.0)

- Grade III

78

(34.7)

42

(43.8)

83

(33.2)

- Grade IV

4

(1.8)

2

(2.1)

4

(1.6)

- Grade V

0

(0)

0

(0)

0

(0)

- Unknown

22

(9.8)

8

(8.3)

21

(8.4)

Surgical approach, n (%)

- Closed

51

(22.7)

12

(12.5)

37

(14.8)

- Open

174

(77.3)

84

(87.5)

213

(85.2)

Duration of surgery (minutes), median [IQR]

316

[206–427]

371

[245–458]

379

[266–514]

- Missing, n (%)

65

(28.9)

21

(21.9)

70

(28.0)

Wound contamination class, n (%)

- Clean-contaminated (class 2)

171

(76.0)

74

(77.1)

184

(73.6)

- Contaminated (class 3)

42

(18.7)

16

(16.7)

50

(20.0)

- Dirty-infected (class 4)

12

(5.3)

6

(6.3)

16

(6.4)

Stoma, n (%)

94

(41.8)

54

(56.3)

139

(55.6)

Malignancy, n (%)

173

(76.9)

77

(80.2)

191

(76.4)

Primary procedure, n (%)

143

(63.6)

53

(55.2)

162

(64.8)

Anastomotic leakage, n (%) *

13

(31.7)

13

(32.5)

36

(39.1)

Surgical site infection, n (%)

- No

165

(73.3)

44

(45.8)

132

(52.8)

- Yes

60

(26.7)

52

(54.2)

118

(46.4)

 - Superficial

19

(31.7)

12

(23.1)

26

(22.0)

 - Deep or organ/space

41

(68.3)

40

(76.9)

92

(78.0)

30-day mortality, n (%)

5

(2.2)

3

(3.1)

6

(2.4)