Table 1.

Risk factors for venous thromboembolism

1	Age
2	Gender
3	Obesity (BMI >30 kgm−2)
4	Personal history of VTE – confirmed previous VTE event >6 months prior
5	Family history of VTE – confirmed VTE in parents or siblings
6	Active malignancy
7	Medical risk factors:
	• General acute or chronic medical immobility for greater than >2 days duration, other than postoperatively. Includes bed rest, overdose with reduced level of consciousness, or wheelchair use in the four weeks preceding the event
	• Relevant chronic medical illness known to predispose to VTE, such as inflammatory bowel disease, cardiomyopathy/congestive heart failure, connective tissue disease including inflammatory arthritis
8	Hormonal:
	• Hormone therapy – hormonal contraceptive or hormone replacement therapy or hormonal antagonist therapy for malignancy
	• Pregnancy
9	Surgery:
	• Surgery – requiring general anaesthetic or spinal/epidural anaesthesia in the four weeks preceding the event
10	Trauma or cast immobility:
	• Trauma – requiring medical attention
	• Cast immobility – orthopaedic limb/foot cast in the 4 weeks preceding the event
11	International air travel:
	• International air travel in the four weeks preceding the event*
12	Prolonged seated immobility: the duration seated at work and at home seated at a computer, in the four weeks preceding the event, defined as:
	• seated at least 10 hours in a 24 hour period and at least 2 hours at a time without getting up

^*International air travel beyond New Zealand involves air flight of ≥3.5 hours