title: 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 thrombosis.
abstract: BACKGROUND
  The optimal duration of oral anticoagulant therapy after a first episode of venous thromboembolism remains controversial.
  
  
  RESULTS
  We performed an open-label, randomized trial comparing a short oral anticoagulant course (3 months for proximal deep vein thrombosis [P-DVT] and/or pulmonary embolism [PE]; 6 weeks for isolated calf DVT [C-DVT]) with a long course of therapy (6 months for P-DVT/PE; 12 weeks for C-DVT). The outcome events were recurrences and major, minor, or fatal bleeding complications. A total of 736 patients were enrolled. There were 23 recurrences of venous thromboembolism in the short treatment group (6.4%) and 26 in the long treatment group (7.4%); the 2 treatment regimens had an equivalent effect. For the hemorrhage end point, the difference between the short and the long treatment groups was not significant: 15.5% versus 18.4% for all events (P=0.302), 1.7% versus 2.8% (P=0.291) for major events, and 13.9% versus 15.3% for minor bleeding. Subgroup analysis demonstrated that the rate of recurrence was lower for C-DVT than for P-DVT or PE.
  
  
  CONCLUSIONS
  After isolated C-DVT, 6 weeks of oral anticoagulation is sufficient. For P-DVT or PE, we demonstrated an equivalence between 3 and 6 months of anticoagulant therapy. For patients with temporary risk factors who have a low risk of recurrence, 3 months of treatment seems to be sufficient. For patients with idiopathic venous thromboembolism or permanent risk factors who have a high risk of recurrence, other trials are necessary to assess prolonged therapy beyond 6 months.
authors.affiliation: Department of Internal Medicine, Centre Hospitalier Universitaire de Lyon, France. laurent.pinede@chu-lyon.fr
authors.forename: L
authors.initials: L
authors.lastname: Pinede
authors.forename: J
authors.initials: J
authors.lastname: Ninet
authors.forename: P
authors.initials: P
authors.lastname: Duhaut
authors.forename: S
authors.initials: S
authors.lastname: Chabaud
authors.forename: S
authors.initials: S
authors.lastname: Demolombe-Rague
authors.forename: I
authors.initials: I
authors.lastname: Durieu
authors.forename: P
authors.initials: P
authors.lastname: Nony
authors.forename: C
authors.initials: C
authors.lastname: Sanson
authors.forename: J P
authors.initials: JP
authors.lastname: Boissel
mesh_terms: D000284:Administration, Oral; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000188:drug therapy; D012008:Recurrence; D013924:Thrombophlebitis / Q000188:drug therapy; D013997:Time Factors; D016896:Treatment Outcome; D014652:Vascular Diseases / Q000188:drug therapy*; D020246:Venous Thrombosis / Q000188:drug therapy
chemical_list: D000925:Anticoagulants