Table 5 Test of proportional hazard assumption (Schoenfeld residuals) for variables, January 1, 2019, to December 31, 2022

Duration of symptoms

0.16

1.81

1

0.19

Presence of comorbidity

0.08

0.49

1

0.48

Abdominal tenderness

-0.07

0.39

1

0.53

Fever

0.06

0.31

1

0.58

abnormal leukocyte count

0.05

0.29

1

0.59

Diagnosis

-0.07

0.51

1

0.48

Preoperative antibiotic use

0.05

0.29

1

0.59

Preoperative hypotension

-0.06

0.30

1

0.58

Preoperative sepsis

0.15

1.84

1

0.18

Degree of peritoneal contamination

0.65

0.35

1

0.55

Pus or faecal matter in peritoneal cavity

-0.10

1.09

1

0.29

Duration of procedures

0.008

0.01

1

0.93

Bowel ischemia

0.08

0.49

1

0.48

Site of Postop care

0.008

0.01

1

0.93

Global test

10.22

15

0.81