OC 42.4 - Venous thromboembolism associated with oestrogen-containing contraceptives versus any hormonal risk factor: a comparison of recurrence rates

Monday, July 11, 2022

3:30 PM – 3:45 PM

Location: ExCel Center, S11B

Presentation Format: In-Person

Presenting Author(s)

JK

Jannet Knijp, MD

MD, PhD student
Amsterdam UMC, University of Amsterdam
Amsterdam, Noord-Holland, Netherlands

Co-Author(s)

Hanke M. Wiegers, MD

PhD Researcher
Department of Obstetrics and Gynaecology, University Medical Centers Amsterdam, University of Amsterdam, Amsterdam, Netherlands
Amsterdam, Noord-Holland, Netherlands
Nick van Es, MD PhD

MD
Department of Vascular Medicine, Amsterdam University Medical Center, Amsterdam, The Netherlands
Amsterdam, Noord-Holland, Netherlands
Michiel Coppens, MD, PhD

Medical Specialist
Department of Vascular Medicine, Amsterdam UMC location University of Amsterdam, Amsterdam, The Netherlands
Amsterdam, Noord-Holland, Netherlands
SM

Stephan Moll

MD, Professor
University of North Carolina School of Medicine
Chapel Hill, North Carolina, United States
Frederikus A. Klok, MD, PhD

MD, PhD
Department of Medicine - Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, the Netherlands
Leiden, Zuid-Holland, Netherlands
Saskia Middeldorp, MD PhD

Professor
Department of Internal Medicine, Radboud university medical center, Nijmegen, The Netherlands
Nijmegen, Gelderland, Netherlands

Background: In many studies reporting on recurrent venous thromboembolism (VTE), oestrogen-containing contraceptives (OCC) as provoking factor is grouped together with other hormonal risk factors, such as hormonal replacement therapy or pregnancy and postpartum state. However, recurrence rates may differ across these groups, which questions whether this approach is justified.

Aims: To compare the pooled recurrence rate of subgroups including young women with OCC-associated VTE exclusively versus women with OCC-associated VTE together with other hormonal risk factors.

Methods: A systematic review and meta-analysis was performed on the risk of recurrence after a first OCC-associated VTE. For the present post-hoc analysis, eligible studies were divided into two groups. The first group included studies that provided data separately for women with OCC-associated VTE with a mean age < 50 years. The second group included studies that provided data for women with OCC-associated VTE, but either within a subgroup of mean age >50 years (i.e. mostly women with hormonal replacement therapy) or combined with pregnancy or postpartum state. Recurrence rates were pooled using Knapp-Hartung random-effects meta-analysis. Differences between groups were tested for significance with the χ2 test.

Results: 26 studies were included [Table 1]. The pooled rate of recurrence was 1.57 (95%CI 1.10-2.23, I2=82%) per 100 patient-years in 14 studies that reported on young women with OCC-associated VTE exclusively compared with 2.46 (95%CI 1.39-4.36, I2=74%) per 100 patient-years in 12 studies that reported on women with OCC-associated VTE, either >50 years or combined with other hormonal factors (p=0.14) [Figure1].

Conclusion(s): The recurrence rate was not significantly lower in studies that reported data for women with OCC-associated VTE than in those grouping OCC with other hormonal risk factors. Since the numerical difference between these groups was nonetheless substantial, interpretation of existing studies and design of future studies on this topic should be cautious in grouping all hormonal causes.