Duration of treatment with vitamin K antagonists in symptomatic venous thromboembolism
- 25 January 2006
- reference entry
- research article
- Published by Wiley
- No. 1,p. CD001367
- https://doi.org/10.1002/14651858.cd001367.pub2
Abstract
Currently, the most frequently used secondary treatment for patients with venous thromboembolism is vitamin K antagonists targeted at an INR of 2.5 (range 2.0 to 3.0). However, based on the continuing risk of bleeding and uncertainty regarding the risk of recurrent venous thromboembolism, there is discussion on the proper duration of treatment with vitamin K antagonists for these patients. Recently, several studies were published in which the risk and benefits of different durations of oral anticoagulants were compared in patients with venous thromboembolism. The objective of this review was to evaluate efficacy and safety of different durations of treatment with vitamin K antagonists in patients with symptomatic venous thromboembolism. The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library Issue 3, 2005). The Specialised Register is constructed from electronic searches of MEDLINE (from inception to October 2005) and EMBASE (inception to October 2005) and through handsearching relevant journals. In addition, we also contacted colleagues for details of trials. The last searches were carried out on 11 October 2005. Randomized controlled clinical trials comparing different durations of treatment with vitamin K antagonists in patients with symptomatic venous thromboembolism. Two reviewers (BH and MP) extracted the data and assessed the quality of the trials independently. Eight studies with a total of 2994 patients were included. A consistent reduction in the risk of recurrent events was observed during prolonged treatment with vitamin K antagonists (OR 0.18; 95% CI 0.13 to 0.26) independent of the period elapsed since the index thrombotic event. A 'rebound' phenomenon, i.e. an excess of recurrences shortly after cessation of the prolonged treatment was not observed (OR 1.24; 95% CI 0.91 to 1.69). In addition, a substantial increase in bleeding complications was found during the entire period after randomization (OR 2.62; 95% CI 1.48 to 4.61). In conclusion, this meta-analysis shows that treatment with vitamin K antagonists reduces the risk of recurrent venous thromboembolism for as long as it is used. However, the absolute risk of recurrent venous thromboembolism declines over time, while the risk for major bleeding remains. Thus, the efficacy of vitamin K antagonist administration decreases over time since the index event.Keywords
This publication has 23 references indexed in Scilit:
- Comparison of 1 month with 3 months of anticoagulation for a first episode of venous thromboembolism associated with a transient risk factorJournal of Thrombosis and Haemostasis, 2004
- Extended Oral Anticoagulant Therapy after a First Episode of Pulmonary EmbolismAnnals of Internal Medicine, 2003
- Three Months versus One Year of Oral Anticoagulant Therapy for Idiopathic Deep Venous ThrombosisNew England Journal of Medicine, 2001
- Comparison of 3 and 6 Months of Oral Anticoagulant Therapy After a First Episode of Proximal Deep Vein Thrombosis or Pulmonary Embolism and Comparison of 6 and 12 Weeks of Therapy After Isolated Calf Deep Vein ThrombosisCirculation, 2001
- A Comparison of Three Months of Anticoagulation with Extended Anticoagulation for a First Episode of Idiopathic Venous ThromboembolismNew England Journal of Medicine, 1999
- The Duration of Oral Anticoagulant Therapy after a Second Episode of Venous ThromboembolismNew England Journal of Medicine, 1997
- A Comparison of Six Weeks with Six Months of Oral Anticoagulant Therapy after a First Episode of Venous ThromboembolismNew England Journal of Medicine, 1995
- A comparison of 3 and 6 weeks' anticoagulation in the treatment of venous thromboembolismClinical and Laboratory Haematology, 1987
- One‐Month versus Six‐Month Therapy with Oral Anticoagulants after Symptomatic Deep Vein ThrombosisActa Medica Scandinavica, 1985
- Antithrombin III in patients with acute deep vein thrombosis during heparin treatment (subcutaneous and intravenous) and during and after treatment with oral coumarinsThrombosis Research, 1984