Epidemiology and incidence: the scope of the problem and risk factors for development of venous thromboembolism.

The proportion of hospitalized patients with pulmonary embolism (PE) is increasing. Whether this represents more admissions with PE or more diagnoses made in hospitalized patients is uncertain. The proportion of hospitalized patients with deep venous thrombosis has decreased precipitously as a result of home treatment. Asians and Native Americans have a lower incidence of PE than whites or African Americans. The incidence of PE increases exponentially with age, but no age group, including infants and children, is immune. Several medical illnesses have now been shown to be associated with a higher risk for venous thromboembolism. Epidemiologic data and new information on risk factors provide insight into making an informed clinical assessment and evaluation for antithrombotic prophylaxis.