PT  - JOURNAL ARTICLE
AU  - Rodger, Marc A.
AU  - Kahn, Susan R.
AU  - Wells, Philip S.
AU  - Anderson, David A.
AU  - Chagnon, Isabelle
AU  - Le Gal, Grégoire
AU  - Solymoss, Susan
AU  - Crowther, Mark
AU  - Perrier, Arnaud
AU  - White, Richard
AU  - Vickars, Linda
AU  - Ramsay, Tim
AU  - Betancourt, Marisol T.
AU  - Kovacs, Michael J.
TI  - Identifying unprovoked thromboembolism patients at low risk for recurrence who can discontinue anticoagulant therapy
AID  - 10.1503/cmaj.080493
DP  - 2008 Aug 26
TA  - Canadian Medical Association Journal
PG  - 417--426
VI  - 179
IP  - 5
4099  - http://www.cmaj.ca/content/179/5/417.short
4100  - http://www.cmaj.ca/content/179/5/417.full
SO  - CMAJ2008 Aug 26; 179
AB  - Background: Whether to continue oral anticoagulant therapy beyond 6 months after an “unprovoked” venous thromboembolism is controversial. We sought to determine clinical predictors to identify patients who are at low risk of recurrent venous thromboembolism who could safely discontinue oral anticoagulants. Methods: In a multicentre prospective cohort study, 646 participants with a first, unprovoked major venous thromboembolism were enrolled over a 4-year period. Of these, 600 participants completed a mean 18-month follow-up in September 2006. We collected data for 69 potential predictors of recurrent venous thromboembolism while patients were taking oral anticoagulation therapy (5–7 months after initiation). During follow-up after discontinuing oral anticoagulation therapy, all episodes of suspected recurrent venous thromboembolism were independently adjudicated. We performed a multivariable analysis of predictor variables (p < 0.10) with high interobserver reliability to derive a clinical decision rule. Results: We identified 91 confirmed episodes of recurrent venous thromboembolism during follow-up after discontinuing oral anticoagulation therapy (annual risk 9.3%, 95% CI 7.7%–11.3%). Men had a 13.7% (95% CI 10.8%–17.0%) annual risk. There was no combination of clinical predictors that satisfied our criteria for identifying a low-risk subgroup of men. Fifty-two percent of women had 0 or 1 of the following characteristics: hyperpigmentation, edema or redness of either leg; D-dimer ≥ 250 μg/L while taking warfarin; body mass index ≥ 30 kg/m2; or age ≥ 65 years. These women had an annual risk of 1.6% (95% CI 0.3%–4.6%). Women who had 2 or more of these findings had an annual risk of 14.1% (95% CI 10.9%–17.3%). Interpretation: Women with 0 or 1 risk factor may safely discontinue oral anticoagulant therapy after 6 months of therapy following a first unprovoked venous thromboembolism. This criterion does not apply to men. (http://Clinicaltrials.gov trial register number NCT00261014)