Table 5 Effect size of two types of anaesthesia on LOS (Days) in prespecified and exploratory subgroups in Each Subgroup

Age (years) group

  < 60

472

0.45

(− 0.03, 0.92)

  > =60, < 70

1011

0.56

(− 0.07, 1.20)

  > =70, < 80

744

1.99

(1.15, 2.83)

  > =80

139

2.46

(−0.29, 5.20)

Sex

 Female

1794

0.62

(0.19, 1.05)

 Male

572

1.58

(0.49, 2.67)

Ethnicity

 Chinese

1987

0.86

(0.38, 1.34)

 Malay

169

0.78

(−0.04, 1.60)

 Indian

137

0.40

(− 0.53, 1.32)

 Others

73

1.53

(−0.46, 3.52)

BMI group

  < 25

726

1.87

(1.06, 2.67)

  > =25, < 30

963

0.28

(−0.36, 0.93)

  > =30, < 35

467

0.38

(−0.26, 1.01)

  > =35

153

0.96

(−0.17, 2.09)

ASA Status

 1

161

−0.01

(− 0.74, 0.73)

 2

2058

0.84

(0.46, 1.21)

 3

147

1.16

(0.46, 1.21)

Hb(g/dL) group

  < 11

164

1.08

(−1.04, 3.19)

  > =11, < 13

888

0.92

(0.17, 1.67)

  > =13

1314

0.79

(0.32, 1.26)

duration of surgery (mins) group

  < 60

320

1.00

(0.28, 1.72)

  > =60, < 120

1903

0.72

(0.25, 1.18)

  > =120

143

1.63

(−0.77, 4.03)

Smoking

 No

2141

0.93

(0.48, 1.37)

 Yes

225

−0.23

(−1.13, 0.68)

OSA

 No

2152

0.88

(0.43, 1.32)

 Yes

214

0.39

(−0.40, 1.18)

DM

 No

1920

0.72

(0.30, 1.15)

 Yes

446

1.32

(0.12, 2.51)

IHD

 No

2239

0.65

(0.25, 1.05)

 Yes

127

4.05

(1.07, 7.02)

CCF

 No

2348

0.91

(0.52, 1.29)

 Yes

18

−5.88

(−36.03, 24.28)

CVA

 No

2321

0.81

(0.39, 1.23)

Yes

45

2.34

(0.34, 4.33)

Creatinine > 2 mg/dl

 No

2090

1.06

(0.64, 1.47)

 Not recorded

258

−0.43

(−1.55, 0.68)

 Yes

18

−7.68

(−26.62, 11.27)

DM on insulin

 No

1764

1.07

(0.57, 1.57)

 Not recorded

563

0.09

(−0.62, 0.79)

 Yes

39

1.04

(−1.10, 3.17)

Day of week of operation

 Monday

390

1.08

(−0.34, 2.49)

 Tuesday

539

0.37

(−0.29, 1.04)

 Wednesday

405

0.40

(−0.28, 1.08)

 Thursday

533

0.60

(0.01, 1.18)

 Friday

378

2.08

(0.60, 3.57)

 Saturday

121

0.15

(−0.69, 0.99)