OC 34.4 - Long-Term Risk of Clinically Relevant Non-Major Bleeding During Extended Anticoagulation for Unprovoked Venous Thromboembolism: A Systematic Review and Meta-Analysis

Monday, July 11, 2022

11:30 AM – 11:45 AM

Location: ExCel Center, ICC Capital Suite Room 14-16

Presentation Format: In-Person

Presenting Author(s)

Faizan Khan, MSc

Postdoctoral Fellow
University of Calgary
Ottawa, Ontario, Canada

Co-Author(s)

Tobias Tritschler, MD, MSc

MD, MSc
Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
Bern, Bern, Switzerland
PW

Philip S. Wells

MD, MSc
Department of Medicine, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada
Ottawa, Ontario, Canada
Gregoire Le Gal, MD PhD

MD, PhD
Ottawa Hospital Research Institute, University of Ottawa, Canada
Ottawa, Ontario, Canada
MR

Marc A. Rodger

Professor
Department of Medicine, McGill University, McGill University Health Center, Montreal, Quebec, Canada
Montreal, Quebec, Canada
DF

Dean Fergusson

Senior Scientist
Ottawa Hospital Research Institute
Ottawa, Ontario, Canada

Background: Clinically relevant non-major bleeding (CRNMB) is an important safety outcome in clinical studies of venous thromboembolism (VTE) as it incurs time consuming management, a decreased perception of quality of life, and important healthcare costs. However, reliable estimates for the long-term risk of CRNMB among patients with unprovoked VTE that are receiving extended anticoagulation are lacking.

Aims: To determine the incidence of CRNMB during extended anticoagulation of up to 5 years among patients with a first unprovoked VTE.

Methods: MEDLINE, Embase, and the the Cochrane Central Register of Controlled Trials were systematically searched for
randomized controlled trials (RCTs) and prospective cohort studies reporting CRNMB events (as defined by the Internatinal Society on Thrombosis and Haemostasis or by the individual studies) among patients with a first unprovoked VTE who were to receive oral anticoagulation for a minimum of 6 additional months after completing at least 3 months of initial anticoagulant treatment. Unpublished data required for analyses were obtained from authors of included studies.

Results: Among the 8 RCTs and 7 cohort studies included in the analysis, 8443 patients received a vitamin K antagonist (VKA) and 6838 received a direct oral anticoagulant (DOAC). The incidence of CRNMB per 100 person-years was 6.48 events (95% CI, 4.69 to 8.55 events) with VKAs and 5.01 events (95% CI, 3.71 to 6.49 events) with DOACs. The 5-year cumulative incidence of CRNMB with VKAs was 21.7% (95% CI, 8.9% to 40.0%) [Table 1]. Data were insufficient to estimate incidence of CRNMB beyond 2 years of extended anticoagulation with DOACs.

Conclusion(s): In patients receiving extended oral anticoagulation for unprovoked VTE, the long-term risk of CRNMB is substantial. This risk may be important to consider in determining treatment duration for patients in whom the risk-benefit ratio of major bleeding and recurrent VTE is closely balanced.