Risk factors

There are several known risk factors for VTE. The following risk factors should be assessed when evaluating your risk of blood clots

HOSPITAL STAYS OR INSTITUTIONALIZATION – Almost half of all VTE cases can be attributed to stays in hospitals or nursing homes within the three last months prior to the event.  VTE is the leading cause of preventable deaths in Norwegian hospitals.

IMMOBILIZATION – Being immobilized for long periods of time, as with hospital bed confinement or long-haul travel, increases VTE risk. Early mobilization during hospital stays or getting up to walk on flights may prevent blood clot formation.

SURGERY – Having surgery greatly increases VTE risk. Hip and knee surgery, heart surgery and neurosurgery are especially high risk procedures. When having such surgery performed, a prophylactic treatment to prevent blood clots will often be prescribed.

CANCER – Approximately 20 % of all first time VTE events occur in relation to cancer, and persons with cancer have a 4- to 7-fold increased risk of VTE compared with cancer-free persons.

PREGNANCY AND THE POST-PARTUM PERIOD – VTE risk is increased during pregnancy and the first six weeks following birth (the post-partum period).

BIRTH CONTROL PILLS OR HORMONE TREATMENT – Using birth control pills increases VTE risk, and the risk is largest for the so-called third generation oral contraceptives. Women who take birth control pills have a 2- to 6-fold increased risk of VTE, compared to those who do not. Hormone supplementation containing estrogen, used to alleviate menopausal discomfort or to prevent bone loss (osteoporosis), does also increase the risk of VTE.

OBESITY – Obese persons (body mass index over 30) have a 2- to 3-fold increased VTE risk compared to subjects with normal weight.

AGE – VTE incidence increases with age. In the Tromsø study, subjects over the age of 70 had an 11-fold higher risk of VTE compared to those under 50 years of age.

PREVIOUS VTE – If you have been previously diagnosed with a blood clot, you also run a higher risk of having another one. Studies have demonstrated that approximately 30 % of all subjects with VTE will experience a recurrent event within a 10-year period.

HERITABILITY – There are inheritable conditions that increase VTE risk. These conditions are called thrombophilias, and are caused by alterations in one or more of the blood’s coagulation factors, increasing the blood’s propensity for clotting. Almost 10 % of the general population carries one of these alterations, but only a small percentage of these will experience a VTE. Even so, a familial aggregation of VTE is frequently seen in the absence of known inheritable conditions, and a vast amount of research effort is directed at revealing new inheritable causes of VTE.



Page administrator: Helle Jørgensen
Last updated: 20.11.2014 08:27
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