Table 3.

Number of studies for potential factors

Endpoint	VTE*
Total of the endpoint	54
Risk factors	N † (%)
Demographic factors
Age	12 (22%)
Gender	13 (24%)
BMI	6 (11%)
Race	1 (2%)
ASA physical status	3 (6%)
Clinical factors
Underlying diagnosis	3 (6%)
Comorbidity (Charlson index)	3 (6%)
Cardiovascular disease	10 (19%)
Respiratory disease	2 (4%)
Neurological disease	1 (2%)
Liver and kidney disease	2 (4%)
Metabolic disease	7 (13%)
Hematological disease	2 (4%)
Endocrine disease	2 (4%)
Malignancy	4 (8%)
Medication (hormone replacement/herbal)	3 (6%)
Laboratory indexes
Preoperative laboratory index	2 (4%)
Postoperative laboratory index	2 (4%)
Health care provider- related factors
Surgery type	12 (22%)
Surgical technic	5 (9%)
Operating time	4 (8%)
Anesthesia	5 (9%)
Bleeding	1 (2%)
Hospital volume	2 (4%)
Insurance type	1 (2%)
Thromboprophylaxes
Chemoprophylaxis	28 (52%)
Initiating and lasting of the prophylaxis	4 (8%)
Mechanical and physical prophylaxis	5 (9%)

*VTE = venous thromboenbolism,which includes DVT(deep vein thrombosis) and PE (pulmonary embolism).

^†Column percentages,not mutually exclusive.