Table 1 Characteristics of study population (N = 551)

a) Patient characteristics

 - Sex (male, %)

276 (64.0)

58 (48.3)

0.002

 - Age (years. old)

71 [61, 79]

79 [72, 84]

 < 0.001

Pre-existing disease (%)

325 (75.4)

97 (80.8)

0.268

 - CNS (%)

37 (8.6)

12 (10.0)

0.591

  - Cerebrovascular Disease (%)

27 (6.3)

8 (6.7)

0.834

 - Cardiovascular (%)

199 (46.2)

72 (60.0)

0.01

  - Ischemic heart disease (%)

38 (8.8)

23 (19.2)

0.003

  - Others (%)

186 (43.2)

61 (50.8)

0.147

      - Arrythmia (%)

40 (9.3)

14 (11.7)

0.487

 - Respiratory (%)

46 (10.7)

7 (5.8)

0.16

  - Acute (%)

9 (2.1)

1 (0.8)

0.698

  - Chronic (%)

27 (6.3)

4 (3.3)

0.268

 - Liver (%)

3 (0.7)

5 (4.2)

0.014

  - Liver cirrhosis (%)

2 (0.5)

3 (2.5)

0.072

 - Kidney (%)

27 (6.3)

15 (12.5)

0.031

  - Hemodialysis (%)

21 (4.9)

12 (10.0)

0.049

b) Preoperative information

Etiology

 - Upper GI perforation (%)

90 (20.9)

14 (11.7)

0.025

 - Lower GI perforation (%)

160 (37.1)

41 (34.2)

0.593

 - Obstruction/strangulation (%)

101 (23.4)

19 (15.8)

0.081

 - Intestinal ischemia/necrosis (%)

42 (9.7)

45 (37.5)

 < 0.001

 - Anastomotic leakage (%)

27 (6.3)

3 (2.5)

0.169

 - GI hemorrhage (%)

10 (2.3)

2 (1.7)

1

 - Other GI disease (%)

19 (4.4)

4 (3.3)

0.798

Blood

 - Hemoglobin (g/dL)

12.4 [10.6, 14.4]

10.7 [9.1, 13.1]

 < 0.001

 - WBC (/dL)

10,100 [5600, 14450]

9450 [4950, 14175]

0.552

 - Platelet (10^4/dL)

22.0 [16.7, 29.3]

14.3 [8.3, 22.9]

 < 0.001

 - Serum creatinine (mg/dL)

0.93 [0.64, 1.8]

1.53 [0.87, 2.38]

 < 0.001

 - Bilirubin (mg/dL)

0.7 [0.5, 1.1]

1.0 [0.6, 2.1]

 < 0.001

 - CRP (mg/dL)

8.4 [0.84, 21.7]

10.4 [4.1, 19.3]

0.177

General conditions

 - SOFA score (points)

2 [1, 5]

8 [5,11]

 < 0.001

 - Glasgow Coma Scale (points)

15 [14,15]

13 [8,15]

 < 0.001

 - Shock (%)

80 (18.6)

74 (61.7)

 < 0.001

 - Mechanical ventilation (%)

64 (14.8)

60 (50.0)

 < 0.001

 - P/F ratio (mmHg)

403 [317, 486]

359 [230, 473]

0.006