Table 2 Outcomes of meta analysis

Patient-related factors

Age (years)

9

2131

0%

0.69

Fixed-effects

WMD

1.21[0.10, 2.31]

0.03*

Age (≥ 65 years old)

6

1256

40%

0.14

Fixed-effects

OR

1.40[1.03, 1.91]

0.03*

Sex (male)

11

2644

13%

0.32

Fixed-effects

OR

1.37[1.08, 1.73]

0.009*

BMI (kg/m²)

6

1438

0%

0.87

Fixed-effects

WMD

-0.11[-0.67, 0.44]

0.69

Smoking

2

954

0%

0.56

Fixed-effects

OR

1.21[0.10, 2.31]

0.10

Comorbidity

4

1271

0%

0.64

Fixed-effects

OR

1.73[1.24, 2.40]

0.001*

ASA score ≥ 3

10

2543

57%

0.01

Random-effects

OR

2.13[1.27, 3.55]

0.004*

Tumor-related factors

Location (≤ 5 cm)

5

1598

0%

0.55

Fixed-effects

OR

1.22 [0.90, 1.65]

0.20

Location (cm)

3

1094

0%

0.52

Fixed-effects

WMD

-0.45[-0.95, 0.67]

0.09

Metastasis

6

1157

50%

0.07

Random-effects

OR

5.94[3.10,11.39]

< 0.001*

Preoperative Hb (g/dL)

2

463

0%

0.99

Fixed-effects

WMD

-0.61 [-1.56, 0.33]

0.20

Preoperative Alb (g/dL)

2

463

0%

0.47

Fixed-effects

WMD

-1.21[-5.95, 3.54]

0.62

CEA (ng/ml)

2

251

25%

0.25

Fixed-effects

WMD

1.44[-15.17, 18.05]

0.87

Treatment-related factors

NRT

9

2477

23%

0.24

Fixed-effects

OR

1.07 [0.82, 1.41]

0.21

NCT

5

996

0%

0.60

Fixed-effects

OR

0.76 [0.50, 1.16]

0.20

History of abdominal surgery

6

1732

34%

0.18

Fixed-effects

OR

1.24 [0.87, 1.76]

0.23

Open surgery

5

1018

66%

0.02

Random-effects

OR

2.26[1.09, 4.67]

0.03*

Incidence of TI non-closure

13

3026

61%

0.002

Random-effects

RD

0.16[0.13, 0.19]

< 0.001*