Table 3 Risk factors of VAS

Age

1.07

0.94–1.22

Gender

 Male

Reference

 Female

1.09

0.27–4.31

Weight

1.02

0.95–1.11

Height

0.97

0.88–1.06

Dosage of fentanyl

1.30

0.96–1.76

Operation time

0.76

0.19–3.02

CYP3A4 *1G

 *1/*1

Reference

 *1/*1G + *1G/*1G

2.09

0.49–8.86

OPRM1 A118G

 GG

Reference

 GA + AA

14.73

3.21–67.49

COMT Val158Met

 GG

Reference

 GA + AA

0.87

0.22–3.46

CYP3A5 *3

 GG

Reference

 GA + AA

0.43

0.08–2.34