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Lifelong treatment with blood thinners is unlikely to have survival benefits for most patients with unexplained clots


août 3, 2023

Dr. Dean Fergusson“Understandings of the trade-offs of taking blood thinners for life can help patients and physicians work together to make the best choices,” said Dr. Dean Fergusson.More than 750,000 Canadians will have an unexplained vein blood clot, known as venous thrombosis. Guidelines suggest that these people take blood thinners for life to prevent a second clot, however, the tradeoffs between the benefits, risks and financial costs of lifelong treatment are unknown. 

A new study led by Dr. Faizan Khan in Dr. Dean Fergusson’s group used a mathematical model to estimate these factors over a patient’s lifetime. Published in Annals of Internal Medicine, the model compared clinical outcomes and costs between two hypothetical groups of 1000 people aged 55 years – one group who took blood thinners for life and another group who stopped treatment after three to six months. 

The authors found that lifelong treatment with blood thinners prevented 368 vein blood clots, including 14 fatal blood clots in the lungs, but also resulted in 114 major bleeding events, including 30 brain bleeds and 11 fatal bleeds. Life-long blood thinners cost $16,014 more per person. 

Overall, the mortality tradeoffs between the two groups were tightly balanced, and patients who stopped treatment only lived an additional month of perfect health. These findings underscore the importance of incorporating patients’ values and preferences when deciding on a treatment strategy.

 “Understandings of the trade-offs of taking blood thinners for life can help patients and physicians work together to make the best choices,” said Dr. Dean Fergusson, a senior scientist at The Ottawa Hospital, Director of the hospital’s Clinical Epidemiology Program and professor at the University of Ottawa.

Authors: Faizan Khan, Doug Coyle, Kednapa Thavorn, Sasha van Katwyk, Tobias Tritschler, Brian Hutton, Gregoire Le Gal, Marc A. Rodger, Dean A. Fergusson

Funding: Canadian Institutes of Health Research. All research at The Ottawa Hospital is enabled by generous donors to The Ottawa Hospital Foundation.

Core resources: Ottawa Methods Centre