Table 3. Cox regression analysis of postoperative VTE.

NO.	Items	B	p-value	Exp(B)	95% CI for Exp(B)
X1	Sex	0.043	0.709	1.044	(0.832, 1.311)
X2	Age	0.103	<0.001	1.108	(1.091, 1.126)
X3	Region	-0.019	0.862	0.981	(0.787, 1.221)
X4	Hospital stay	0.010	0.343	1.010	(0.989, 1.032)
X5	VTE history	1.602	<0.001	4.962	(3.849, 6.397)
X6	Hypertension	0.296	0.007	1.344	(1.084, 1.667)
X7	Diabetes	0.163	0.337	1.177	(0.844, 1.642)
X8	Heart disease	-0.337	0.190	0.731	(0.431, 1.182)
X9	Fusion	-0.313	0.166	0.731	(0.470, 1.139)
X10	Levels of fusion	0.102	0.232	1.107	(0.937, 1.309)
X11	Surgical duration	-0.001	0.311	0.999	(0.996, 1.001)
X12	Blood loss	<0.001	0.514	1.000	(0.999, 1.000)
X13	Blood transfusion	<0.001	0.237	1.000	(1.000, 1.001)
X14	Incision length	0.002	0.871	1.002	(0.981, 1.023)
X15	PTA	0.006	0.123	1.006	(0.998, 1.013)
X16	FIB	<0.001	0.997	1.000	(0.843, 1.186)
X17	TT	0.021	0.673	1.021	(0.927, 1.125)
X18	D-dimer	0.095	0.464	1.099	(0.853, 1.417)
X19	HDL	0.113	0.148	1.119	(0.961, 1.305)
X20	LDL	0.082	0.352	1.086	(0.913, 1.290)
X21	TC	0.007	0.933	1.007	(0.862, 1.176)
X22	TBIL	-0.002	0.955	0.998	(0.926, 1.075)
X23	DBIL	0.042	0.470	1.043	(0.930, 1.169)
X24	IBIL	-0.004	0.921	0.996	(0.924, 1.074)
X25	BMI	0.004	0.826	1.004	(0.972, 1.037)

VTE, venous thromboembolism; CI, confidence interval; PTA, prothrombin time activity; FIB, fibrinogen; TT, thrombin time; HDL, high density lipoprotein; LDL, low density lipoprotein; TC, total cholesterol; T-BIL, total bilirubin; D-BIL, direct bilirubin; I-BIL, indirect bilirubin; BMI, body mass index.