Table 6 Risk factors for postoperative VTE

Variable

p value

Age ≥50 years

<0.01

Age ≥55 years

<0.01

Malignant disease

<0.01

Operating time ≥4 hours

<0.05

Blood loss ≥1,000 ml

<0.05

Blood loss ≥1,500 ml

<0.05

Blood loss ≥2,000 ml

<0.01

Blood transfusion ≥2,000 ml

<0.05

Multivariate analysis

Variable

Risk ratio

95% CI

p value

Lower

Upper

Allergic-immunologic disease

4.816

1.010

22.956

<0.05

Malignant disease

6.035

1.881

19.359

<0.01

Blood transfusion ≥2,000 ml

6.206

1.248

30.862

<0.05