Epidemiology and risk factors of venous thromboembolism.

Venous thromboembolism (VTE) is a common disorder that can affect apparently healthy as well as hospitalized patients. The actual incidence and prevalence of this disease are difficult to estimate because of its often silent nature. The clinical relevance of VTE is highlighted by the important rates of recurrence and mortality. The individual risk of VTE varies as a result of a complex interaction between congenital and transient or permanent acquired risk factors. Risk factors can be either intrinsic (e.g., age, obesity, history of VTE, or thrombophilia) or disease related (e.g., surgical procedures and medical disorders such as cancer, heart failure, or acute respiratory failure). The presence or absence of specific risk factors may play an important role in decisions about the type (and duration) of thromboprophylaxis/anticoagulation to be used.