Table 2 Baseline data on SSI and non-SSI of patients in the training cohort

Number

288

259

29

Age (years)^a

61.75 ± 9.82

61.44 ± 9.63

64.48 ± 11.24

BMI (kg/m²)^a

24.68 ± 3.06

24.64 ± 3.00

25.00 ± 3.58

Height (mm)^a

162.16 ± 7.59

162.10 ± 7.49

162.66 ± 8.54

Weight (kg)^a

64.96 ± 9.63

64.82 ± 9.40

66.29 ± 11.64

The total volume of drainage (mL)^a

310.12 ± 133.13

309.20 ± 133.21

318.31 ± 134.48

The last volume of drainage (mL)^a

28.95 ± 18.56

28.29 ± 18.73

34.86 ± 16.08

The duration of drainage (days)^a

5.84 ± 1.10

5.86 ± 1.08

5.59 ± 1.30

Lengths of admission (days)^a

14.01 ± 4.24

13.96 ± 4.11

14.41 ± 5.35

Albumin (g/L)^a

34.39 ± 3.27

34.40 ± 3.31

34.23 ± 2.97

The highest CRP (mg/L)^a

38.95 ± 30.24

37.59 ± 28.49

51.12 ± 41.47

The last CRP (mg/L)^a

22.85 ± 22.80

22.83 ± 22.69

23.06 ± 24.15

The highest WBC count (109/L)^a

12.98 ± 3.41

12.93 ± 3.31

13.43 ± 4.24

The last WBC count (109/L)^a

8.71 ± 2.94

8.71 ± 2.77

8.70 ± 4.26

The highest ESR count (mm/h)^a

24.98 ± 18.29

24.31 ± 18.17

30.93 ± 18.58

The last ESR count (mm/h)^a

22.94 ± 17.08

22.65 ± 17.18

25.52 ± 16.17

Subcutaneous fat thickness (mm)^a

12.42 ± 5.94

12.08 ± 5.84

15.42 ± 6.13

LPM fat infiltration (%)^a

28.07 ± 11.14

26.90 ± 10.57

38.50 ± 10.75

Gender^b

Female

138 (47.9%)

127 (49.0%)

11 (37.9%)

Male

150 (52.1%)

132 (51.0%)

18 (62.1%)

Drinking^b

No

242 (84.0%)

219 (84.6%)

23 (79.3%)

Yes

46 (16.0%)

40 (15.4%)

6 (20.7%)

Physical work

117 (40.6%)

107 (41.3%)

10 (34.5%)

Others

166 (57.6%)

150 (57.9%)

16 (55.2%)

Education^b

Primary and secondary school

266 (92.4%)

239 (92.3%)

27 (93.1%)

High school

7 (2.4%)

7 (2.7%)

0 (0.0%)

College

15 (5.2%)

13 (5.0%)

2 (6.9%)

Maximum body temperature (°C)^b

36.5–38

206 (71.5%)

182 (70.3%)

24 (82.8%)

38–39

76 (26.4%)

72 (27.8%)

4 (13.8%)

> 39

6 (2.1%)

5 (1.9%)

1 (3.4%)

Surgery duration (h)^b

< 3

120 (41.7%)

119 (45.9%)

1 (3.4%)

3–4

119 (41.3%)

110 (42.5%)

9 (31.0%)

≥ 4

49 (17.0%)

30 (11.6%)

19 (65.5%)

Postoperative prophylactic antibiotics (days)^b

< 3

187 (64.9%)

167 (64.5%)

20 (69.0%)

3–7

64 (22.2%)

58 (22.4%)

6 (20.7%)

≥ 7

37 (12.8%)

34 (13.1%)

3 (10.3%)