Table 4.

References of studies for potential factors

Risk factors	Reference number’s for papers
Demographic factors
Age	[22,23,26,28-30,35,41,47,52,54,63]
Gender	[18,22,23,26,28-30,35,41,47,52-54]
BMI	[26,28-30,35,54]
Race	[23]
ASA physical status	[35,52,54]
Clinical factors
Underlying diagnosis	[26,46,47]
Comorbidity (Charlson index)	[23,47,54]
Cardiovascular disease	[18,22,26,29,30,35,47,53,54,62]
Respiratory disease	[35,58]
Neurological disease	[35]
Liver and kidney disease	[47,61]
Metabolic disease	[26,35,37,47,53,59,64]
Hematological disease	[26,35]
Endocrine disease	[26,35]
Malignancy	[26,35,47,53]
Medication (hormone replacement/herbal)	[18,26,29]
Laboratory indexes
Preoperative laboratory index	[35,49]
Postoperative laboratory index	[28,53]
Health care provider- related factors
Surgery type	[11,13,18,20,21,26,27,29,30,35,41,53]
Surgical technic	[12,13,18,21,29]
Operating time	[19,22,35,49]
Anesthesia	[18,21,29,30,52]
Bleeding	[28]
Hospital volume	[23,55]
Insurance type	[23]
Thromboprophylaxes
Chemoprophylaxis	[14-18,21,25,26,28,31-34,36,38-40,42-45,47,48,50,51,56,60,61]
Initiating and lasting of the prophylaxis	[21,30,43,57]
Mechanical and physical prophylaxis	[19,24,29,30,52]