Analysis of risk factors for postoperative deep vein thrombosis after craniotomy and nomogram model construction

Table 1 Univariate analysis of the risk factors for deep vein thrombosis

Risk factors	No (%) of DVT (n = 135)	No (%) of No-DVT (n = 148)	Univariate
			HR (95%CI)	P value
Gender (male)	52 (38.5)	74 (50.0)	0.627 (0.390-1.006)	0.053
Age (yr)	NA	NA	1.072 (1.048-1.097)	< 0.001
BMI (kg/m2)	NA	NA	0.988 (0.927-1.054)	0.718
Smoking history	31 (23.0)	31 (20.9)	1.125 (0.640-1.977)	0.682
Glucose	NA	NA	1.276 (1.109-1.468)	0.001
PLT	NA	NA	0.999 (0.995-1.002)	0.474
D-dimer (≥ 1.08 mg/L)	88 (65.2)	48 (32.4)	3.901 (2.381-6.391)	< 0.001
Infections	44 (32.6)	17 (11.5)	3.726 (2.004-6.929)	< 0.001
Malignant tumor	61 (45.2)	38 (25.7)	2.386 (1.446-3.938)	0.001
Carprini	NA	NA	1.810 (1.511-2.168)	< 0.001
Hemostatic drugs (days)	NA	NA	0.926 (0.782-1.096)	0.371
Steroid	61 (45.2)	33 (22.3)	2.873 (1.717-4.805)	< 0.001
Operation time	NA	NA	1.786 (1.486-2.148)	< 0.001
Transfusion	16 (11.9)	5 (3.4)	8.525 (3.207-22.664)	< 0.001
IPC	9 (6.7)	62 (41.9)	0.200 (0.109-0.366)	< 0.001

This table shows the proportion of each included factor in the outcome event, Continuous data are shown as means ± standard deviations (SD) and compared by Student’s t-test. Categorical data are expressed as numbers and percentages and were compared by χ² test. BMI: Body mass index; DVT: Deep vein thrombosis; IPC: Intermittent pneumatic compression; PLT: Platelet; HR: Hazard ratio

Table 2 Multivariate analysis of the risk factors for deep vein thrombosis

Risk factors	β	Sx	P value	OR	95%CI
					Lower limit	Upper limit
Age	0.062	0.017	< 0.001	1.064	1.029	1.100
D-dimer	1.681	0.375	< 0.001	5.368	2.575	11.190
Infections	1.268	0.476	0.008	3.553	1.397	9.039
Carprini	0.548	0.143	< 0.001	1.731	1.308	2.290
Steroid	0.963	0.397	0.015	2.619	1.203	5.706
Operation time	0.369	0.143	0.010	1.446	1.093	1.914
Transfusion	1.342	0.657	0.041	3.828	1.056	13.873
IPC	-2.370	0.486	< 0.001	0.094	0.036	0.242

The P value and 95% confidence interval of the final included factors were calculated using the binary metalogic regression equation. IPC: Intermittent pneumatic compression.