Long-term Risk of Recurrent Venous Thromboembolism after a First Contraceptive-related Event: Data from REVERSE Cohort Study

D. Aziz^1,2, L. Skeith^3,4, M. Rodger^5,6, E. Sabri¹, M. Righini⁷, M. Kovacs⁸, M. Carrier^1,2, S. Kahn^5,9, P. Wells^1,2, D. Anderson¹⁰, I. Chagnon¹¹, S. Solymoss⁵, M. Crowther¹², R. White¹³, G. Le Gal^1,2

¹The Ottawa Hospital, Ottawa, Canada, ²University of Ottawa, Ottawa, Canada, ³University of Calgary, Calgary, Canada, ⁴Foothills Medical Centre, Calgary, Canada, ⁵McGill, Montreal, Canada, ⁶McGill University Health Centre, Montreal, Canada, ⁷Geneva University Hospital, Geneva, Switzerland, ⁸Lawson Health Research Institute, London, Canada, ⁹Jewish General Hospital, Montreal, Canada, ¹⁰Dalhousie University, Halifax, Canada, ¹¹Hôpital du Sacré-Cœur-de-Montréal, Montreal, Canada, ¹²McMaster University, Hamilton, Canada, ¹³University of California, Davis, United States

Abstract Number: PB1237

Meeting: ISTH 2021 Congress

Theme: Venous Thromboembolism » VTE Treatment

Background: The reported risk of recurrent venous thromboembolism (VTE) after a combined oral contraceptive (COC) associated VTE is heterogeneous.

Aims: We assessed the long-term risk of recurrent VTE in women on COC at the time of a first VTE, in comparison to women without COC use. Our secondary aim assessed the impact of COC use on the recurrent VTE risk in high risk and low risk HERDOO2 subgroups.

Methods: The REVERSE cohort study derived the HERDOO2 clinical decision rule to predict recurrent VTE in patients who discontinued anticoagulation after 5-7 months for a first unprovoked VTE. Incidence rates of recurrent VTE among women with and without COC exposure were calculated as the number of recurrent VTE over the number of person-years of follow-up, and Cox proportional hazards model was used to compare risks between groups.

Results: The risk of recurrent VTE among COC users was 1.1% (95% CI 0.3-2.9) per patient-year as compared with 3.2% per patient-year (95% CI 2.4-4.3) among non-users (HR, 0.37, 95% CI, 0.1-1.0). Women who were COC users and high risk by HERDOO2 score had a recurrence rate of 3.5% (95% CI 0.4-12.5) as compared to 6.1% (95% CI 4.3-8.5) among women who were non-COC users and at high risk by HERDOO2 score (HR 0.6, 95% CI, 0.1-2.5).

Conclusions: Women who were COC users at the time of an otherwise unprovoked VTE event had a lower VTE recurrence rate during long-term follow-up, compared to non-users. The use of HERDOO2 rule may help identify higher risk women with COC use.

To cite this abstract in AMA style:

Aziz D, Skeith L, Rodger M, Sabri E, Righini M, Kovacs M, Carrier M, Kahn S, Wells P, Anderson D, Chagnon I, Solymoss S, Crowther M, White R, Le Gal G. Long-term Risk of Recurrent Venous Thromboembolism after a First Contraceptive-related Event: Data from REVERSE Cohort Study [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/long-term-risk-of-recurrent-venous-thromboembolism-after-a-first-contraceptive-related-event-data-from-reverse-cohort-study/. Accessed September 29, 2023.

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