Comparison of 1 month with 3 months of anticoagulation for a first episode of venous thromboembolism associated with a transient risk factor

C. Kearon*, J. S. Ginsberg, D. R. Anderson, M. J. Kovacs, P. Wells, J. A. Julian, B. MacKinnon, C. Demers, J. Douketis, A. G. Turpie, P. van Nguyen, D. Green, J. Kassis, S. R. Kahn, S. Solymoss, L. Desjardins, W. Geerts, M. Johnston, J. I. Weitz, J. HirshM. Gent

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

129 Scopus citations

Abstract

Background: The risk of recurrence is lower after treatment of an episode of venous thromboembolism associated with a transient risk factor, such as recent surgery, than after an episode associated with a permanent, or no, risk factor. Retrospective analyses suggest that 1 month of anticoagulation is adequate for patients whose venous thromboembolic event was provoked by a transient risk factor. Methods: In this double-blind study, patients who had completed 1 month of anticoagulant therapy for a first episode of venous thromboembolism provoked by a transient risk factor were randomly assigned to continue warfarin or to placebo for an additional 2 months. Our goal was to determine if the duration of treatment could be reduced without increasing the rate of recurrent venous thromboembolism during 11 months of follow-up. Results: Of 84 patients assigned to placebo, five (6.0%) had recurrent venous thromboembolism, compared with three of 81 (3.7%) assigned to warfarin, resulting in an absolute risk difference of 2.3% [95% confidence interval (CI) - 5.2, 10.0]. The incidence of recurrent venous thromboembolism after discontinuation of warfarin was 6.8% per patient-year in those who received warfarin for 1 month and 3.2% per patient-year in those who received warfarin for 3 months (rate difference of 3.6% per patient-year; 95% CI - 3.8, 11.0). There were no major bleeds in either group. Conclusion: Duration of anticoagulant therapy for venous thromboembolism provoked by a transient risk factor should not be reduced from 3 months to 1 month as this is likely to increase recurrent venous thromboembolism without achieving a clinically important decrease in bleeding.

Original languageEnglish (US)
Pages (from-to)743-749
Number of pages7
JournalJournal of Thrombosis and Haemostasis
Volume2
Issue number5
DOIs
StatePublished - May 2004

Keywords

  • Anticoagulation
  • Randomized trial
  • Risk Factor
  • Transient venous thromboembolism
  • Treatment
  • Warfarin

ASJC Scopus subject areas

  • Hematology

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