Table 3 Summary of characteristics in PS and non-PS studies

 Male

4/5

0.94 [0.65,1.35]; P=0.73/1.83 [1.43, 2.34]; P<0.01

I²=0%; P=0.91/I²=13%; P=0.33

 Age

4/3

2.66 [0.96, 4.36]; P=0.002/6.21 [4.24, 8.19]; P<0.01

I²=25%; P=0.26/I²=57%; P=0.10

 BMI

4/4

−0.13 [−0.60, 0.34]; P=0.58/0.21 [−0.16, 0.58]; P=0.26

I²=0%; P=0.98/I²=38%; P=0.18

 T1-T2

3/4

2.04 [0.40, 10.28]; P=0.39/1.79 [0.30, 10.74]; P=0.53

I²=0%; P=0.49/I²=65%; P=0.04

 T3-T4

3/4

0.49 [0.10, 2.48]; P=0.39/0.56 [0.09, 3.37]; P=0.53

I²=0%; P=0.49/I²=65%; P=0.04

 TG

2/2

1.56 [0.42, 5.88]; P=0.51/0.87 [0.53, 1.44]; P=0.60

I²=0%; P=0.98/I²=0%; P=0.72

 SG

2/2

0.64 [0.17, 2.41]; P=0.51/1.14 [0.72, 1.80]; P=0.58

I²=0%; P=0.98/I²=0%; P=0.73

 B-I or B-II

2/2

0.91 [0.55, 1.52]; P=0.72/1.13[0.31, 4.09]; P=0.85

I²=0%; P=0.84/I²=77%; P=0.04

 Roux-en-Y

2/2

1.10 [0.66, 1.83]; P=0.72/0.96 [0.30, 3.04]; P=0.94

I²=0%; P=0.84/I²=67%; P=0.08

 Blood loss

2/4

12.97 [−60.39, 86.34]; P=0.73/−6.44 [−17.08, 4.20]; P=0.24

I²=91%; P=0.0007/I²=11%; P=0.34

 Operation time

3/4

−5.27 [−13.08, 2.55]; P=0.19/−6.48[−13.02, 0.06]; P=0.05

I²=0%; P=0.39/I²=24%; P=0.27

 Retrieved LNs

3/3

−2.33 [−7.87, 3.21]; P=0.41/−3.14 [−5.01, −1.27]; P=0.001

I²=82%; P=0.004/I²=0%; P=0.70

 Metastatic LNs

4/3

0.96 [0.50, 1.81]; P=0.89/0.52 [0.30, 0.92]; P=0.02

I²=0%; P=0.62/I²=12%; P=0.32

 PHS

2/4

0.60 [−1.25,2.45]; P=0.52/0.53 [−0.37, 1.43]; P=0.25

I²=0%; P=1.00/I²=0%; P=0.95

 Overall

4/5

1.25 [0.81, 1.92]; P=0.32/1.11[0.80, 1.54]; P=0.53

I²=0%; P=0.75/I²=15%; P=0.32

 AL

3/4

1.18 [0.22, 6.28]; P=0.84/1.21 [0.49, 2.97]; P=0.68

I²=0%; P=0.77/I²=0%; P=0.45

 AS

2/2

2.27 [0.59, 8.74]; P=0.24/0.86 [0.23, 3.28]; P=0.83

I²=0%; P=0.49/I²=0%; P=0.92

 Ileus

2/5

1.90 [0.45, 8.01]; P=0.38/ 1.66 [0.85, 3.25]; P=0.14

I²=0%; P=0.72/I²=39%; P=0.16

 Abdominal infection

2/3

0.46 [0.05, 4.47]; P=0.50/2.06 [0.87, 4.87]; P=0.10

I²=0%; P=0.76/I²=0%; P=0.61

 Gastric stasis

2/3

0.60 [0.15, 2.36]; P=0.47/0.79 [0.27, 2.28]; P=0.66

I²=0%; P=0.38/I²=0%; P=0.98

 Wound infection

3/3

2.31 [0.78, 6.86]; P=0.13/1.33[0.53, 3.36]; P=0.55

I²=0%; P=0.65/I²=0%; P=0.96

 PL

3/2

2.17 [0.59, 7.97]; P=0.24/0.80 [0.23, 2.77]; P=0.72

I²=0%; P=0.37/I²=9%; P=0.29

 PB

2/2

0.71 [0.18, 2.81]; P=0.63/0.67 [0.12, 3.59]; P=0.64

I²=0%; P=0.96/I²=0%; P=0.91