Patient preferences must be considered for anticoagulation duration in unprovoked VTE

Shared decision making should be practiced by clinicians to include patient preferences and values when taking into account the duration of anticoagulant therapy for unprovoked venous thromboembolism (VTE), suggests a study.

A group of researchers conducted this Markov modeling study to estimate the benefit‒harm tradeoffs of indefinite anticoagulant therapy in patients with a first unprovoked VTE. They obtained data on the long-term risks and case-fatality rates of recurrent VTE and major bleeding from systematic reviews and meta-analyses, and data on costs, quality of life, and other clinical events from published literature.

The following outcomes were assessed: recurrent VTE events, major bleeding events, costs in 2022 Canadian dollars (CAD), and quality-adjusted life-years (QALYs).

On base-case analysis, indefinite anticoagulation prevented 368 recurrent VTEs, including 14 fatal pulmonary emboli, but provoked an additional 114 major bleeding events, including 30 intracranial haemorrhages and 11 deaths from bleeding, when compared with discontinuing therapy after initial treatment in a hypothetical cohort of 1,000 patients aged 55 years.

The cost of indefinite anticoagulation was CAD 16,014 more per person and did not increase QALYs (‒0.075 per person).

Sensitivity analysis revealed that the results of the model were most sensitive to the case-fatality rate of major bleeding and the annual risk for major bleeding during extended anticoagulation.

One limitation of this study was the assumption of the model that risks for recurrent VTE and major bleeding measured in clinical trials at 1 year remained constant during extended anticoagulation.