Key Points
- To quantify the risks and benefits of extending the duration of anticoagulation therapy in patients with venous thromboembolism.
- Systematic review and meta-analysis of randomized controlled trials published from 1969 through 2004 identified through PubMed, EMBase Pharmacology, Cochrane database, and clinical trial registries.
- Included 15 trials evaluating anticoagulation duration and recurrent venous thromboembolism, excluding pure populations of high-risk patients.
- Extracted data on recurrent venous thromboembolism, major bleeding, person-time at risk, and trial quality across long-term versus short-term therapy arms.
- During active treatment, long-term anticoagulation significantly reduced recurrent VTE compared to short-term therapy (0.020 vs 0.126 events/person-year; rate difference -0.106, 95% CI -0.145 to -0.067, P < .001; pooled IRR 0.21, 95% CI 0.14 to 0.31, P < .001).
- After discontinuing extended anticoagulation, the reduction in recurrent VTE risk was attenuated but remained significant (0.052 vs 0.072 events/person-year; rate difference -0.020, 95% CI -0.039 to -0.001, P = .04; pooled IRR 0.69, 95% CI 0.53 to 0.91, P = .009).
- The risk of major bleeding did not differ significantly between long-term and short-term therapy arms (0.011 vs 0.006 events/person-year; rate difference 0.005, 95% CI -0.002 to 0.011, P = .14; pooled IRR 1.80, 95% CI 0.72 to 4.51, P = .21).
Structured PICO
Does extended duration of anticoagulation reduce recurrent VTE in patients with venous thromboembolism?
PPopulationPatients with venous thromboembolism (VTE) from 15 randomized controlled trials. Excluded: pure populations of high-risk patients.
IInterventionExtended duration of anticoagulation (long-term therapy)
CComparatorShort-term anticoagulation
OOutcomeRecurrent VTEhard clinical
Extended anticoagulation protects against recurrent VTE while on therapy, with a smaller but maintained benefit after discontinuation, without a significant increase in major bleeding.