Risk of post-thrombotic syndrome after subtherapeutic warfarin anticoagulation for a first unprovoked deep vein thrombosis: results from the REVERSE study
Version of Record online: 1 OCT 2012
© 2012 International Society on Thrombosis and Haemostasis
Journal of Thrombosis and Haemostasis
Volume 10, Issue 10, pages 2039–2044, October 2012
How to Cite
CHITSIKE, R. S., RODGER, M. A., KOVACS, M. J., BETANCOURT, M. T., WELLS, P. S., ANDERSON, D. R., CHAGNON, I., LE GAL, G., SOLYMOSS, S., CROWTHER, M. A., PERRIER, A., WHITE, R. H., VICKARS, L. M., RAMSAY, T. and KAHN, S. R. (2012), Risk of post-thrombotic syndrome after subtherapeutic warfarin anticoagulation for a first unprovoked deep vein thrombosis: results from the REVERSE study. Journal of Thrombosis and Haemostasis, 10: 2039–2044. doi: 10.1111/j.1538-7836.2012.04872.x
- Issue online: 1 OCT 2012
- Version of Record online: 1 OCT 2012
- Accepted manuscript online: 30 JUL 2012 04:18AM EST
- Received 6 May 2012, accepted 23 July 2012
- post-thrombotic syndrome;
- risk factor;
- venous thrombosis;
Summary. Background: Risk factors for post-thrombotic syndrome (PTS) remain poorly understood.
Objectives: In this multinational multicenter study, we evaluated whether subtherapeutic warfarin anticoagulation was associated with the development of PTS.
Methods: Patients with a first unprovoked deep venous thrombosis (DVT) received standard anticoagulation for 5–7 months and were then assessed for PTS. The time in the therapeutic range was calculated from the international normalized ratio (INR) data. An INR below 2, more than 20% of the time, was considered as subtherapeutic anticoagulation.
Results: Of the 349 patients enrolled, 97 (28%) developed PTS. The overall frequency of PTS in patients with subtherapeutic anticoagulation was 33.5%, compared with 21.6% in those with an INR below two for ≤ 20% of the time (P = 0.01). During the first 3 months of therapy, the odds ratio (OR) for developing PTS if a patient had subtherapeutic anticoagulation was 1.78 (95% confidence interval [CI] 1.10–2.87). After adjusting for confounding variables, the OR was 1.84 (95% CI 1.13–3.01). Corresponding ORs for the full period of anticoagulation were 1.83 (95% CI 1.14–3.00) [crude] and 1.88 (95% CI 1.15–3.07) [adjusted].
Conclusion: Subtherapeutic warfarin anticoagulation after a first unprovoked DVT was significantly associated with the development of PTS.