Prophylaxis against venous thromboembolism in hospitalized medical patients: an evidence-based and practical approach.

To discuss the evidence regarding the efficacy and safety of anticoagulant prophylaxis against deep vein thrombosis (DVT) in hospitalized medical patients; to understand barriers to implementation of prophylaxis and how they can be overcome; and to have a practical approach as to which patients should and should not receive anticoagulant prophylaxis. The frequency of DVT in hospitalized medical patients, in the absence of prophylaxis varies from 10-15%. Autopsy studies have shown that pulmonary embolism (PE) is associated with 5-10% of deaths in hospitalized patients. With appropriate use of anticoagulant prophylaxis, there is a 57% reduction in the risk for symptomatic PE (relative risk [RR] 0.43, 95% CI 0.26-0.71), a 62% reduction in the risk for fatal PE (RR 0.38, 95% CI 0.21-0.69), and a 53% reduction in the risk for symptomatic DVT (RR 0.47, 95% CI 0.22-1.00). Anticoagulant prophylaxis is also associated with a non-significant increased risk for major bleeding (RR 1.32, 95% CI 0.73-2.37). Risk factors for DVT and bleeding in medical patients may help to identify patients in whom anticoagulant prophylaxis is indicated or contraindicated but validated risk stratifications schemes are lacking. Among hospitalized medical patients, randomized trials have established an acceptable therapeutic benefit-to-risk ratio of anticoagulant prophylaxis to reduce the incidence of clinically silent and symptomatic venous thromboembolism, including a reduction in the incidence of fatal PE. Additional research is needed to develop a validated risk stratification model for hospitalized medical patients that can help identify patients who would benefit most from anticoagulant prophylaxis.