Table 3 Analysis of risk factors associated with postoperative SSIs in CRC patients

Gender

0.476

 Male

269 (62.4%)

246 (61.8%)

23 (69.7%)

Ref

Ref

 Female

162 (37.6%)

152 (38.2%)

10 (30.3%)

0.71 [0.31;1.50]

0.379

Age

66.0 [56.0;72.0]

66.0 [57.0;72.0]

65.0 [55.0;71.0]

0.99 [0.96;1.02]

0.48

0.409

Height

162 [155;168]

162 [155;168]

160 [156;169]

1.01 [0.96;1.05]

0.77

0.948

Weight

57.0 [50.0;65.0]

57.0 [50.0;65.0]

62.3 [54.0;68.0]

1.03 [1.00;1.07]

0.041

0.053

BMI

21.9 [19.9;24.0]

21.8 [19.8;24.0]

23.3 [21.5;24.6]

1.12 [1.02;1.23]

0.017

0.026

COVID-19 pandemic

0.578

 No

274 (63.6%)

255 (64.1%)

19 (57.6%)

Ref

Ref

 Yes

157 (36.4%)

143 (35.9%)

14 (42.4%)

1.32 [0.63;2.71]

0.461

Hypertension

0.932

 No

291 (67.5%)

268 (67.3%)

23 (69.7%)

Ref

Ref

 Yes

140 (32.5%)

130 (32.7%)

10 (30.3%)

0.90 [0.40;1.92]

0.798

Diabetes

0.008

 No

398 (92.3%)

372 (93.5%)

26 (78.8%)

Ref

Ref

 Yes

33 (7.66%)

26 (6.53%)

7 (21.2%)

3.88 [1.42;9.48]

0.01

HepatitisB

1

 No

388 (90.0%)

358 (89.9%)

30 (90.9%)

Ref

Ref

 Yes

43 (9.98%)

40 (10.1%)

3 (9.09%)

0.93 [0.21;2.80]

0.914

Gallstones

1

 No

400 (92.8%)

369 (92.7%)

31 (93.9%)

Ref

Ref

 Yes

31 (7.19%)

29 (7.29%)

2 (6.06%)

0.88 [0.13;3.13]

0.861

Surgical history

0.502

 No

396 (91.9%)

364 (91.5%)

32 (97.0%)

Ref

Ref

 Yes

35 (8.12%)

34 (8.54%)

1 (3.03%)

0.38 [0.02;1.85]

0.282

Tumor location

0.184

 Colon

237 (55.0%)

223 (56.0%)

14 (42.4%)

Ref

Ref

 Rectum

194 (45.0%)

175 (44.0%)

19 (57.6%)

1.72 [0.84;3.62]

0.138

Tumor stage

0.884

 I

68 (15.8%)

64 (16.1%)

4 (12.1%)

Ref

Ref

 II

127 (29.5%)

118 (29.6%)

9 (27.3%)

1.20 [0.37;4.71]

0.776

 III

190 (44.1%)

173 (43.5%)

17 (51.5%)

1.53 [0.54;5.62]

0.451

 IV

46 (10.7%)

43 (10.8%)

3 (9.09%)

1.13 [0.20;5.65]

0.883

Preoperative chemotherapy

0.659

 No

411 (95.4%)

380 (95.5%)

31 (93.9%)

Ref

Ref

 Yes

20 (4.64%)

18 (4.52%)

2 (6.06%)

1.45 [0.20;5.40]

0.654

Surgical start time (days)

5.00 [3.00;7.00]

5.00 [3.00;7.00]

5.00 [4.00;8.50]

1.09 [1.01;1.18]

0.024

0.281

Hair removal

1

 No

354 (83.1%)

327 (83.0%)

27 (84.4%)

Ref

Ref

 Yes

72 (16.9%)

67 (17.0%)

5 (15.6%)

0.93 [0.30;2.32]

0.879

Bowel preparation

0.589

 No

97 (22.7%)

88 (22.3%)

9 (28.1%)

Ref

Ref

 Yes

330 (77.3%)

307 (77.7%)

23 (71.9%)

0.73 [0.33;1.72]

0.45

Bowel preparation methods

0.833

 None

16 (3.71%)

15 (3.77%)

1 (3.03%)

Ref

Ref

 OABP only

79 (18.3%)

72 (18.1%)

7 (21.2%)

1.31 [0.20;35.2]

0.811

 MBP only

9 (2.09%)

8 (2.01%)

1 (3.03%)

1.83 [0.04;77.6]

0.72

 MBP + OABP

327 (75.9%)

303 (76.1%)

24 (72.7%)

1.05 [0.20;26.2]

0.962

Surgical wound class

0.169

 Clean-contaminated

390 (92.0%)

362 (92.6%)

28 (84.8%)

Ref

Ref

 Contaminated or dirty

34 (8.02%)

29 (7.42%)

5 (15.2%)

2.27 [0.72;5.95]

0.151

Grade of lead surgeon

0.074

 Senior

315 (73.1%)

286 (71.9%)

29 (87.9%)

Ref

Ref

 Middle

116 (26.9%)

112 (28.1%)

4 (12.1%)

0.36 [0.10;0.96]

0.04

Surgical approach

0.036

 Laparoscopic

342 (79.4%)

321 (80.7%)

21 (63.6%)

Ref

Ref

 Open

89 (20.6%)

77 (19.3%)

12 (36.4%)

2.39 [1.09;5.02]

0.031

Surgical duration (hours)

3.17 [2.45;3.92]

3.11 [2.42;3.83]

3.63 [2.83;4.20]

1.36 [1.01;1.84]

0.046

0.021

Colostomy/ileostomy

0.002

 No

304 (70.5%)

289 (72.6%)

15 (45.5%)

Ref

Ref

 Yes

127 (29.5%)

109 (27.4%)

18 (54.5%)

3.17 [1.53;6.62]

0.002

Postoperative bowel obstruction

1

 No

399 (92.6%)

368 (92.5%)

31 (93.9%)

Ref

Ref

 Yes

32 (7.42%)

30 (7.54%)

2 (6.06%)

0.84 [0.12;3.01]

0.822