Table 1.

Preoperative characteristics of patients

Variables	Nonchemoprophylaxis group	Chemoprophylaxis group	P
Number of patients	4965	1904
Age (years), mean	51.86	59.7	<0.001
Sex (male) (%)	56	47	<0.001
BMI (kg/m2), mean	28.11	29.31	<0.001
Smoking (% current smoker)	15	12	<0.001
VTE history (%)	2.10	5.80	<0.001
Epidural hematoma history	0.07	0.13	0.4
Bleeding disorder history	2.20	3.60	<0.001
Neurological deficit (%)	4	6	0.004
Number of comorbidities (mean)	1.89	2.69	<0.001

BMI - Body mass index; VTE - Venous thromboembolism