Table 1 Characteristics of all included trials

Auer 2022 Auer et al. 2022)

0.0

Thrombo-prophylaxis

Colorectal

NS

12

No

High

614

61.1 (12.9)

-

28.4 (5.6)

-

Yes↑

-

Yes↑

-

Yes

-

No

Fafaj 2022 Fafaj et al. 2022)

0.3

Catheter

Colorectal

NS

6

No

High

491

60 (12.6)

-

26.1 (3.7)

28.1

Yes↑

-

No

Yes↓

No

-

No

Gao 2022 Gao et al. 2022)

0.5

Nutrition

Colorectal

S

11

No

Fair

229

60.1 (11.3)

62.4 (7.8)

22.9 (3.1)

-

Yes↑

Yes↓

Yes↓

-

No

Yes

Yes

Aoyama 2022 Aoyama et al. 2022)

0.6

Nutrition

UGI

NS

8

No

High

123

63.7 (12.2)

46.7 (6.7)

-

-

No

Yes↓

-

-

No

Yes

-

Hakovirta 2022 Hakovirta et al. 2022)

0.6

Inflammatory mediators

Vascular

NS

9

No

High

38

73.5 (9.0)

-

-

-

Yes↑

-

-

-

Yes

-

-

Cao 2021 Cao et al. 2021)

0.8

Somatostatin

HPB

S

6

No

Fair

199

58.5 (11.0)

-

23 (3)

-

Yes↑

-

Yes↓

-

No

-

Yes

de Waal 2021 Waal et al. 2021)

1.0

Goal-directed therapy

Mixed

NS

2 + 

No

High

482

65.4 (11.4)

78.2 (15.6)

25.9 (4.4)

38.6

Yes↑

No

Yes↓

Yes↑

Yes

No

No

Marschalek 2021 Marschalek et al. 2531)

1.2

Hormone therapy

Gynae

NS

2

No

Fair

103

62.7 (10.0)

-

27.1 (4.4)

-

Yes↑

-

No

-

Yes

-

No

Papp 2021 Papp et al. 2021)

1.6

Antibiotics

Colorectal

S

4

No

High

529

66.3 (12.2)

-

27.2 (4.4)

-

Yes↑

-

No

-

Yes

-

No

Hortu 2020 Hortu et al. 2020)

2.2

Local anaesthetic

Gynae

S

2

No

Low

108

52.2 (6.2)

-

29.7 (4.6)

-

Yes↑

-

No

-

No

-

No

Mulder 2020 Mulder et al. 2020)

2.3

Antibiotics

Colorectal

S

6

No

Fair

78

67.2 (8.5)

-

26.8 (4.9)

28.2

Yes↑

-

No

No

Yes

-

No

Boggett 2020 Boggett et al. 2020)

2.4

Neuromuscular blockade

Mixed

NS

4

No

High

350

54.5 (15.9)

-

29.2 (6.1)

24.4

No

-

Yes↑

Yes↓

No

-

No

Espin Basany 2020 Espin Basany et al. 2020)

2.4

Antibiotics

Colorectal

S

5

No

High

536

70.8 (12.6)

-

27.6 (4.1)

48.9

Yes↑

-

Yes↑

-

Yes

-

No

Bohlin 2020 Bohlin et al. 2020)

2.6

Smoking cessation

Gynae

S

2 + 

No

High

651

48 (10.0)

-

-

1.8

No

-

-

Yes↓

No

-

-

Futier 2020 Futier et al. 2020)

2.7

IV fluids

Mixed

NS

20

No

Low

775

68.5 (7.0)

81.5 (12.8)

27.5 (5.5)

48.6

Yes↑

Yes↓

No↑

Yes↑

Yes

No

No

Bretagnol 2020 Bretagnol et al. 2010)

2.9

Bowel prep

Colorectal

S

8

No

Fair

178

63.5 (3.1)

-

25 (0.8)

-

Yes↑

-

No

-

Yes

-

No

Linecker 2020 Linecker et al. 2015)

3.0

Omega 3

HPB

NS

3

No

Low

261

58.2 (15.8)

-

24.8 (3.7)

-

Yes↑

-

Yes↓

-

No

-

Yes

De Milliano 2019 Milliano et al. 2020)

3.1

Hormone therapy

Gynae

S

9

No

High

54

39.8 (5.9)

-

26.2 (5.5)

-

Yes↓

-

No

-

No

-

No

Bruintjes 2019 Bruintjes et al. 2019)

3.5

Neuromuscular blockade

Urology

NS

2

No

Fair

96

56.2 (9.9)

-

26.6 (2.9)

-

Yes↓

-

No

-

No

-

No

Habib 2019 Habib et al. 2019)

3.7

Antiemetics

Mixed

S

23

No

Low

702

46.3 (10.9)

-

-

-

Yes↓

-

-

-

No

-

-

Karanicolas 2018 Karanicolas et al. 2018)

4.2

Wound infusion catheters

HPB

S

2

No

Low

153

62.7 (12.6)

-

-

-

Yes↑

-

-

-

Yes

-

-

Springer 2018 Springer et al. 2018)

4.3

Post-op ileus

Colorectal

NS

2

No

Low

118

65 (14)

-

28.6 (6)

94.9

Yes↑

-

Yes↑

Yes↑

Yes

-

No

Kranke 2018 Kranke et al. 2018)

4.3

Antiemetics

Mixed

S

29

No

Low

1147

48.5 (14)

-

30.3 (8.6)

-

Yes↓

-

Yes↑

-

No

-

Yes

Sang 2018 Sang et al. 2018)

4.3

Thrombo-prophylaxis

Gynae

S

5

No

High

625

53.7 (10.3)

-

24.9 (3.8)

-

Yes↑

-

Yes↓

-

No

-

No

de Leede 2018 Leede et al. 2018)

4.6

Post-op ileus

Mixed

NS

12

No

Low

1941

65.8 (12.9)

-

25.6 (6.8)

17.9

Yes↑

-

Yes↓

Yes↓

Yes

-

No

Peters 2018 Peters et al. 2018)

4.6

Nutrition

Colorectal

NS

6

No

Low

265

68.5 (8.9)

-

26.2 (4.1)

15.5

Yes↑

-

No

Yes↓

Yes

-

No

Boden 2018 Boden et al. 2018)

4.7

Pre-hab

Mixed

S

3

No

Low

432

64.3 (14.7)

-

28.4 (6)

36.4

Yes↑

-

Yes↑

Yes↑

No

-

No

Chanques 2017 Chanques et al. 2017)

5.0

Sedation

Mixed

S

3

No

Low

137

67.8 (14.1)

-

25.8 (4.8)

-

Yes↑

-

Yes↓

-

Yes

-

No

Brunschot 2017 Özdemir-van Brunschot et al. 2018)

5.3

Neuromuscular blockade

Urology

S

2

No

Low

34

-

-

25.5 (3.7)

-

-

-

Yes↓

-

-

-

No

Keeler 2017 Keeler et al. 2017)

5.7

Iron

Colorectal

NS

7

UK only

Fair

116

73.9 (9.0)

75.7 (12.2)

-

37.1

Yes↑

No

-

No

Yes

No

-

Burden 2017 Burden et al. 2017)

5.7

Nutrition

Colorectal

S

6

UK only

Low

101

69.8 (11.6)

-

25.7 (4.7)

23.1

Yes↑

-

No

Yes↓

Yes

-

No

Loozen 2017 Loozen et al. 2017)

5.8

Antibiotics

HPB

NS

6

No

Low

150

53.2 (10.4)

-

-

-

No

-

-

-

No

-

-

Topsoee 2016 Topsoee et al. 2016)

6.2

TXA

Gynae

S

4

No

Low

332

48.5 (8.6)

-

25.4 (4.7)

0.3

No

-

Yes↓

Yes↓

No

-

No

Piljic 2016 Piljic et al. 2016)

6.3

IV fluids

Vascular

S

2

No

High

60

69 (8.0)

-

-

-

Yes↑

-

-

-

Yes

-

-

Jaber 2016 Jaber et al. 2016)

6.5

NIV

Mixed

S

20

No

Low

293

63.4 (13.8)

-

27.2 (10.1)

-

Yes↑

-

No

-

No

-

No

Atkinson 2016 Atkinson et al. 2016)

6.6

Post-op ileus

Colorectal

NS

5

UK only

Fair

402

66.2 (12.9)

-

27.5 (5.1)

22.1

Yes↑

-

Yes↑

Yes↓

Yes

-

No

Fushida 2015 Fushida et al. 2015)

7.0

Tiotropium

UGI

NS

15

No

High

82

-

-

22.5 (2.6)

-

-

-

Yes↓

-

-

-

Yes

Hamza 2015 Hamza et al. 2015)

7.7

Nutrition

HPB

S

3

UK only

High

37

65.2 (9.9)

-

24.4 (5.6)

-

Yes↑

-

Yes↓

-

Yes

-

Yes

van den Heijkant 2015 Heijkant et al. 2015)

7.8

Post-op ileus

Colorectal

S

2

No

High

120

66.5 (10.1)

78.5 (11.9)

26.5 (4.5)

10.8

Yes↑

Yes↓

No

Yes↓

Yes

No

No

Pestana 2014 Pestana et al. 2014)

8.1

Goal-directed therapy

Mixed

NS

6

No

Low

142

72.3 (11.6)

72.9 (14.8)

26.8 (4.4)

51.4

Yes↑

Yes↓

No

Yes↑

Yes

No

No

Regimbeau et al. (2014) Regimbeau et al. 2014

8.2

Antibiotics

HPB

NS

17

No

High

414

55.5 (12.4)

-

-

-

Yes↑

-

-

-

No

-

-

Kakkar 2014 Kakkar et al. 2014)

8.3

Thrombo-prophylaxis

Mixed

NS

2 + 

-

High

4352

61.9 (11.9)

-

25.6 (8.5)

-

Yes↑

-

Yes↓

-

No

-

No

Vedovati 2014 Vedovati et al. 2014)

8.5

Thrombo-prophylaxis

Colorectal

S

5

No

Fair

225

64.8 (9.0)

-

25.3 (3.4)

-

Yes↑

-

No

-

Yes

-

No

Young 2013 Young et al. 2013)

9.0

Communication

Colorectal

NS

23

No

Fair

756

67.8 (12.2)

-

-

-

Yes↑

-

-

-

Yes

-

-

Giger-Pabst 2013 Giger-Pabst et al. 2013)

9.4

Nutrition

Colorectal

NS

6

No

High

108

64.1 (12.7)

75.4 (10.2)

-

-

Yes↑

No

-

-

Yes

No

-

Muller 2012 Muller et al. 2012)

10.0

Post-op ileus

Colorectal

S

3

No

Fair

79

60.5 (13.5)

-

-

29.1

Yes↑

-

-

Yes↑

No

-

-

Stott 2012 Stott et al. 2012)

10.1

Laxatives

Colorectal

S

2

No

Fair

45

65.6 (14.3)

-

-

-

Yes↑

-

-

-

Yes

-

-

Phoolcharoen 2012 Phoolcharoen et al. 2012)

10.3

Antibiotics

Gynae

NS

2

No

Low

320

45.4 (7.0)

-

-

-

Yes↓

-

-

-

No

-

-

Barlow 2011 Barlow et al. 2011)

11.6

Nutrition

UGI

S

3

UK only

High

121

64 (11.1)

73 (13.3)

25.4 (4)

46.3

No

No

Yes↓

Yes↓

No

No

No

Wattchow 2009 Wattchow et al. 2009)

12.9

Post-op ileus

Colorectal

NS

3

No

Low

210

62.1 (14)

77 (18.7)

-

-

Yes↑

No

-

-

Yes

No

-

Meyhoff 2009 Meyhoff et al. 2009)

13.0

Oxygen therapy

Mixed

NS

14

No

Low

1395

64 (20.4)

71.5 (13.4)

25 (4)

19.1

Yes↑

Yes↓

Yes↓

Yes↓

No

No

No

Shimizu 2010 Shimizu et al. 2010)

13.1

Antibiotics

Colorectal

NS

4

No

High

91

69.7 (8.5)

-

-

8.8

Yes↑

-

-

Yes↓

Yes

-

-

Trivedi 2007 Trivedi et al. 2007)

13.2

Hormone therapy

Gynae

S

5

No

High

98

30.9 (9.7)

55.1 (10)

-

-

Yes↓

Yes↓

-

-

Yes

Yes

-

Muller 2009 Muller et al. 2009)

13.6

Enhanced recovery

Colorectal

S

4

No

Fair

151

60.6 (9.6)

-

25.1 (2.8)

27.8

Yes↑

-

No

Yes↓

No

-

No

Ludwig 2008 Ludwig et al. 2008)

13.9

Post-op ileus

Colorectal

S

55

No

Fair

654

59.8 (14)

-

28.4 (6.3)

-

Yes↑

-

Yes↑

-

No

-

No

Godet 2008 Godet et al. 2008)

14.4

IV fluids

Vascular

NS

7

No

High

60

73 (7.8)

73.6 (8.6)

-

-

Yes↑

Yes↓

-

-

Yes

No

-

Del Rio 2008 Rio et al. 2008)

14.5

Antibiotics

HPB

NS

2 + 

No

High

209

53.6 (14.6)

-

-

-

No

-

-

-

No

-

-

Lassen 2008 Lassen et al. 2008)

14.7

Nutrition

UGI

NS

5

No

High

447

64 (13.9)

-

-

-

No↑

-

-

-

No

-

-

Contant 2007 Contant et al. 2007)

14.8

Bowel prep

Colorectal

NS

13

No

High

1354

67 (12.5)

-

-

12.2

Yes↑

-

-

Yes↓

Yes

-

-

Aqua 2007 Aqua et al. 2007)

15.0

Analgesia

Gynae

S

21

No

Low

331

42.7 (9.3)

-

-

-

Yes↓

-

-

-

No

-

-

Skanberg 2007 Skanberg et al. 2007)

15.5

Blood transfusion

Colorectal

NS

7

No

High

642

71.7 (9.5)

-

-

-

Yes↑

-

-

-

Yes

-

-

Han-Geurts 2007 Han-Geurts et al. 2007)

15.6

Post-op ileus

Colorectal

NS

3

No

High

128

63.6 (14.9)

-

27 (7.9)

-

Yes↑

-

No

-

Yes

-

No

Ellison 2007 Ellison et al. 2007)

15.7

Communication

Urology

NS

3

No

High

270

54 (9.8)

-

-

-

Yes↓

-

-

-

No

-

-

Chermesh 2007 Chermesh et al. 2007)

15.7

Probiotics

Colorectal

NS

4

No

High

30

35.6 (11.9)

64.5 (14.3)

-

-

Yes↓

Yes↓

-

-

Yes

No

-

Wichmann 2007 Wichmann et al. 2007)

15.7

Nutrition

Mixed

S

4

No

High

256

59.3 (11.5)

72.6 (13.4)

25.2 (3.9)

-

Yes↑

Yes↓

Yes↓

-

No

No

No

Rasmussen 2006 Rasmussen et al. 2006)

16.2

Thrombo-prophylaxis

Mixed

S

5

No

High

343

66.3 (11.4)

71.5 (14)

-

-

Yes↑

Yes↓

-

-

Yes

No

-

White 2006 White et al. 2006)

16.7

Antiemetics

Mixed

NS

2

No

High

205

38.5 (13.5)

102 (35)

37.5 (10.5)

-

Yes↓

Yes↓

Yes↑

-

Yes

Yes

Yes

Valverde 2006 Valverde et al. 2006)

16.7

Bowel prep

Colorectal

NS

20

No

High

467

66 (12.6)

-

-

-

Yes↑

-

-

-

Yes

-

-

Ming-Tsan 2005 Lin et al. 2005)

17.1

Nutrition

UGI

S

2

No

High

48

67.1 (8.6)

57.2 (9.6)

-

-

Yes↑

Yes↓

-

-

No

Yes

-

Viscusi 2006 Viscusi et al. 2006)

17.2

Post-op ileus

Mixed

S

37

No

High

444

56.5 (11.9)

-

28.5 (6.7)

-

No↑

-

Yes↑

-

No

-

No

Fa-Si-Oen 2005 Fa-Si-Oen et al. 2005)

17.2

Bowel prep

Colorectal

NS

5

No

High

250

68.4 (10.0)

-

-

-

Yes↑

-

-

-

Yes

-

-

Bucher 2005 Bucher et al. 2005)

17.9

Bowel prep

Colorectal

S

2

No

Fair

153

63 (9.9)

-

-

11.8

Yes↑

-

-

Yes↓

Yes

-

-

Malan 2005 Malan et al. 2005)

18.0

Analgesia

Gynae

S

2 + 

-

High

264

44.6 -

81.2 (22.7)

-

-

-

Yes↓

-

-

-

No

-

Wolff 2004 Wolff et al. 2004)

18.0

Post-op ileus

Colorectal

S

34

No

High

469

60.5 (11.4)

-

28.2 (5)

-

Yes↑

-

Yes↑

-

No

-

No

van Hilten 2004 Hilten et al. 2004)

18.4

Blood transfusion

Mixed

NS

19

No

Low

1051

66.5 (11.3)

-

-

-

Yes↑

-

-

-

Yes

-

-

Nordin 2004 Nordin et al. 2004)

18.6

Anaesthetic technique

Colorectal

S

3

No

High

138

56.6 (14.6)

-

24.4 (2.8)

-

Yes↑

-

Yes↓

-

No

-

Yes

Nordin 2003 Nordin et al. 2003)

19.1

Anaesthetic technique

Colorectal

S

10

No

Fair

616

56 (13.7)

-

25 (4)

-

Yes↑

-

No

-

No

-

No

Buppasiri 2004 Buppasiri et al. 2004)

19.1

Decontamination

Gynae

S

3

No

Low

299

43.9 (7.4)

59.3 (9.6)

24.5 (3.6)

-

Yes↓

Yes↓

Yes↓

-

No

Yes

Yes

Chongsomchai 2002 Chongsomchai et al. 2002)

20.0

Antibiotics

Gynae

S

2

No

Low

321

43.6 (6.3)

-

23.9 (3.4)

-

Yes↓

-

Yes↓

-

No

-

Yes

Rigg 2002 Rigg et al. 2002)

20.6

Epidural

Mixed

NS

25

No

Low

915

69 (11.0)

-

-

-

Yes↑

-

-

-

Yes

-

-

Tonelli 2002 Tonelli et al. 2002)

20.7

Antibiotics

Mixed

NS

2 + 

No

High

476

63.6 (13.0)

-

-

-

Yes↑

-

-

-

No

-

-

McLeod 2001 McLeod et al. 2001)

22.1

Thrombo-prophylaxis

Colorectal

NS

10

No

High

1349

51 (17.5)

-

-

-

No

-

-

-

No

-

-

Takala 2000 Takala et al. 2000)

22.7

CVS support

Mixed

NS

13

UK incl

High

432

62.5 (13.4)

70 (14)

-

-

Yes↑

Yes↓

-

-

No

No

-

Zanella 2000 Zanella and Rulli 2000)

22.8

Antibiotics

Colorectal

NS

14

No

High

615

65 (11.2)

-

-

-

Yes↑

-

-

-

Yes

-

-

Verspyck 2000 Verspyck et al. 2000)

23.3

Hormone therapy

Gynae

S

10

No

High

56

41.4 (1.8)

-

24.1 (0.9)

-

Yes↓

-

Yes↓

-

No

-

Yes

Jian 1999 Jian et al. 1999)

23.4

Nutrition

Colorectal

S

4

No

High

120

55 (12.6)

59.7 (9.5)

-

-

Yes↑

Yes↓

-

-

No

Yes

-

Valverde 1999 Valverde et al. 1999)

23.7

Bowel prep

Colorectal

S

18

No

High

523

68 (12.5)

-

-

-

Yes↑

-

-

-

Yes

-

-

Cutillo 1999 Cutillo et al. 1999)

23.8

Nutrition

Gynae

S

3

No

High

122

53.3 (14.1)

-

-

-

Yes↑

-

-

-

No

-

-

Vercellini 1998 Vercellini et al. 1998)

24.2

Hormone therapy

Gynae

S

4

No

Fair

123

45.9 (3.5)

-

23.2 (3.1)

-

Yes↓

-

Yes↓

-

No

-

Yes

Milsom 1998 Milsom et al. 1998)

24.7

Antibiotics

Colorectal

NS

61

No

High

317

59.5 (15.1)

78 (17)

-

-

Yes↑

No

-

-

No

No

-

Heiss 1997 Heiss et al. 1997)

25.2

Blood transfusion

Colorectal

S

3

No

High

70

58.8 (10.0)

-

-

-

Yes↑

-

-

Yes↑

No

-

-

O'Hara 1997 O’Hara et al. 1997)

25.4

Analgesia

Gynae

S

3

No

High

191

43.4 (10.7)

76.6 (22.7)

-

-

Yes↓

No

-

-

No

No

-

Johnson 1997 Johnson et al. 1997)

25.7

Analgesia

Gynae

S

3

No

High

190

41 (11.8)

75.3 (18.4)

-

-

Yes↓

No

-

-

No

No

-

Vickers 1995 Vickers and Paravicini 1995)

27.4

Analgesia

Mixed

NS

26

UK incl

Fair

523

52 (15)

70.5 (12.5)

-

-

Yes↓

Yes↓

-

-

No

No

-

Stankov 1995 Stankov et al. 1995)

27.8

Analgesia

UGI

S

5

No

Low

100

48.8 (14.5)

75.5 (13.7)

-

-

Yes↓

No

-

-

Yes

No

-

Taylor 1994 Taylor et al. 1994)

27.9

Antibiotics

Colorectal

S

13

No

High

327

66.6 (12.9)

-

-

-

Yes↑

-

-

-

Yes

-

-

Stewart 1995 Stewart et al. 1995)

28.7

Antibiotics

Colorectal

S

13

UK incl

High

326

66.6 (12.8)

-

-

-

Yes↑

-

-

-

Yes

-

-

Houbiers 1994 Houbiers et al. 1994)

28.7

Blood transfusion

Colorectal

NS

16

No

High

697

68.5 (14.3)

-

-

-

Yes↑

-

-

-

Yes

-

-

Friess 1994 Fiess et al. 1994)

28.8

Octreotide

HPB

S

18

No

High

246

51.2 (9.7)

-

-

-

No

-

-

-

No

-

-

Gipponi 1993 Gipponi et al. 1993)

29.8

IVIG/sepsis

Colorectal

S

3

No

High

159

65.5 (8.5)

-

-

-

Yes↑

-

-

-

Yes

-

-

Andaker 1992 Andaker et al. 1992)

30.6

Antibiotics

Colorectal

NS

9

No

High

517

66.5 (14)

68.5 (11.5)

-

-

Yes↑

Yes↓

-

-

Yes

No

-

Arnaud 1992 Arnaud et al. 1992)

30.7

Antibiotics

Colorectal

NS

19

No

Fair

208

66 (12.0)

68 (13)

-

-

Yes↑

Yes↓

-

-

Yes

No

-

Rotman 1991 Rotman et al. 1991)

30.9

Antibiotics

Mixed

NS

24

No

High

1254

50.9 (18.7)

-

-

-

Yes↓

-

-

-

No

-

-

DiPiro 1989 DiPiro et al. 1989)

33.8

Antibiotics

Colorectal

NS

3

No

High

195

53.9 (17.5)

-

-

-

No

-

-

-

No

-

-

Rotman 1989 Rotman et al. 1989)

34.4

Antibiotics

Mixed

NS

2 + 

-

High

3137

47.6 (17.8)

-

-

-

Yes↓

-

-

-

No

-

-

Walker 1988 Walker et al. 1988)

34.9

Antibiotics

Colorectal

NS

7

UK only

High

213

63.5 (10.6)

-

-

-

Yes↑

-

-

-

Yes

-

-