Venous thromboembolism in medical patients--the scope of the problem.

The risk of venous thromboembolism (VTE) in medical patients has been substantially underestimated and prophylaxis is used far less than it is in surgical patients, reflecting the scarcity of evidence supporting antithrombotic therapy in nonsurgical settings. Reports of the frequency of deep venous thrombosis (DVT) in general medical patients in the absence of prophylaxis vary from 10 to 26%, depending on the methods used for diagnosis of DVT and the patient population studied. The risk in specific groups may be higher and may exceed that reported in low- or moderate-risk surgical patients. Data from several studies show that DVT developed in approximately 55% of patients with stroke, 24% of patients with myocardial infarction, and, in general medical populations, congestive heart failure, respiratory distress and/or underlying chest infections appeared to increase the risk of VTE. The frequency of VTE in patients with congestive heart failure has been reported to be as high as 40%. In a study among patients in a medical intensive care unit, it was found that 33% had VTE, of which 48% were proximal leg thromboses. Many other medical conditions increase the risk of thromboembolic events. These include malignant disease, which is commonly associated with a hypercoagulable state; inflammatory conditions such as systemic lupus erythematosus and inflammatory bowel disease; coma; and nephrotic syndrome. Accurate risk assessment and prompt implementation of appropriate prophylaxis, selected on the basis of evidence from well-designed, controlled clinical trials, may reduce future morbidity and mortality due to VTE in medical patients.