Prolonged outpatient vitamin K antagonist use and risk of venous thromboembolism in patients undergoing total hip or knee replacement

A. Lalmohamed, P. Vestergaard, P. A. F. Jansen, E. L. Grove, A. de Boer, Hubertus G. M. Leufkens, Tjeerd P. van Staa, F. de Vries*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

4 Citations (Web of Science)

Abstract

Background Long-term risk of venous thromboembolism (VTE) following total hip or knee replacement (THR/TKR) compared with controls has not been studied extensively, and the long-term influence of outpatient anticoagulant use on VTE risk remains unknown. The objectives were to evaluate long-term VTE risk following THR/TKR compared with matched controls, and to investigate effect modification by prolonged outpatient vitamin K antagonist use. Methods A Danish retrospective nationwide cohort study was conducted. All patients undergoing primary THR/TKR (n=95,227) between 1998 and 2007 were selected, each matched by age, sex and region with three controls (no THR/TKR). Patients were stratified by prolonged outpatient vitamin K antagonist use in the previous 3months (in a time-dependent manner). All subjects were followed for VTE, and Cox models were used to calculate disease and medication history adjusted hazard ratios (HRs). Results Within 6weeks following surgery, a 13-fold increased risk of VTE was found for THR (adj. HR 12.9; 95% CI 11.214.7), and a 14-fold elevated risk for TKR (adj. HR 13.6; 95% CI 11.016.7), compared with matched controls. The risk remained substantially increased for at least 4months following THR/TKR. Within this period, prolonged outpatient vitamin K antagonist use reduced the increase in VTE risk by 69% for THR and 54% for TKR. Conclusion The risk of VTE remains substantially elevated for at least 4months following THR/TKR; this is well beyond the recommended duration of anticoagulant use. The increase in VTE risk is less pronounced in prolonged outpatient vitamin K antagonist users.
Original languageEnglish
Pages (from-to)642-650
JournalJournal of Thrombosis and Haemostasis
Volume11
Issue number4
DOIs
Publication statusPublished - Apr 2013

Keywords

  • arthroplasty
  • replacement
  • hip
  • knee
  • pharmacoepidemiology
  • pulmonary embolism
  • venous thromboembolism
  • venous thrombosis

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