OC 60.2 - Bleeding during initial and extended anticoagulant treatment in VTE patients compared to matched population controls without anticoagulant medication – a Swedish nationwide register-based study.

Tuesday, June 25, 2024

15:00 - 15:15 ICT

Room: Plenary Hall

Presenting Author(s)

Katarina Glise Sandblad, MD, PhD

Attending physician
Region Västra Götaland, Sahlgrenska University Hospital/Östra, Department of Medicine, Geriatrics and Emergency Medicine, Gothenburg, Sweden.
Göteborg, Vastra Gotaland, Sweden

Co-Author(s)

Sam Schulman

Hematologist
McMaster University
Hamilton, Ontario, Canada
AR

Annika Rosengren

Professor
Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
Gothenburg, Vermont, Sweden
TZ

Tatiana Zverkova Sandström

Statistician
Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Gothenburg, Vastra Gotaland, Sweden
MT

Mazdak Tavoly

PhD, MD
Department of Medicine, Sahlgrenska University Hospital
Gothenburg, Vastra Gotaland, Sweden
PH

Per-Olof Hansson

Associate professor
Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Gothenburg, Vastra Gotaland, Sweden

Background: The magnitude of increased bleeding risk during anticoagulant treatment following a venous thromboembolism (VTE) depends on both the anticoagulant treatment and the baseline bleeding risk in the population.

Aims: To determine the risk of bleeding in patients on anticoagulant treatment compared to matched population controls, stratified by age and sex.

Methods: Nationwide Swedish register-based study including all cancer-free first-time VTE patients with a dispense of direct oral anticoagulant medication 2014–2020 compared to cancer-free matched population controls without VTE and anticoagulant treatment. Rates of major bleeding (hospitalization or death due to bleeding) were compared during both initial (0–6 months) and extended (6 months–5 years) treatment using 1:1 propensity score matching and Cox regression.

Results: Among 40,039 VTE cases and 149,597 controls, 39,396 of each group remained after propensity score matching. The incidence rate (IR) of major bleeding during initial treatment was 2.75 per 100 person-years and 0.63 in controls, yielding an adjusted hazard ratio (aHR) of 4.48 (3.58–5.61). In patients over 80 years, the IR was 5.92 in cases and 1.87 in controls, with an aHR of 3.22 (2.34–4.43). During extended treatment, the IR was 1.06 per 100 person-years for VTE cases and 0.62 for controls, with an aHR of 1.79 (1.34–2.40). In patients over 80, the IR was 1.98 in cases and 1.35 in controls, with an aHR of 1.64 (1.01–2.65). There was a tendency towards a higher risk increase in women than men on anticoagulation compared to controls.

Conclusion(s): The anticoagulant-related and the baseline risk of bleeding in the population depended on age and sex. In initial treatment, the relative risk tended towards a higher increase in groups with low baseline risk. The risk of bleeding in extended treatment was low and, in certain age groups, not significantly different from controls.