predisposing factors

Last edited 06/2018 and last reviewed 09/2023

Some risk factors suggest greater risk of venous thromboembolism than others:

  • strong risk factors (odds ratio > 10)
    • fracture (hip or leg)
    • hip or knee replacement
    • major general surgery
    • major trauma
    • spinal cord injury

  • intermediate risk factors (odds ratio 2 to 9)
    • arthroscopic knee surgery
    • central venous lines
    • chemotherapy
    • chronic heart or respiratory failure
    • hormone therapy
    • malignancy
    • oral contraceptive therapy
    • paralytic stroke
    • pregnancy/postpartum
    • previous venous thromboembolism
    • thrombophilia

  • weak risk factors (odds ratio < 2)
    • bed rest longer than 3 days
    • immobility due to sitting (e.g. – car or air travel longer than eight hours_
    • increasing age
    • laproscopic surgery
    • obesity (BMI>40kg/mm2)
    • pregnancy/antepartum
    • varicose veins (1)

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