Starting Testosterone Associated With Increased Risk of Blood Clots Interview with:
Dr. Carlos Martinez

Institute for Epidemiology, Statistics and Informatics GmbH
Frankfurt, Germany, What is the background for this study?

Response: A 10-fold increase in testosterone prescriptions per capita in the United States and a 40-fold increase in Canada in men has occurred over the first decade of this century, mainly for sexual dysfunction and/or decreased energy. Recognised pathological disorders of the male reproductive system remain the sole unequivocal indication for testosterone treatment but there has been increasing use in men without pathological hypogonadism. A variety of studies and meta-analyses have provided conflicting evidence as to the magnitude of the risk of cardiovascular events including venous thromboembolism in men on testosterone treatment.

In June 2014, the US Food and Drug Administration and Health Canada required a warning about the risk of venous thromboembolism to be displayed on all approved testosterone products. Studies have reported contradictory results on an association between testosterone use and the risk of venous thromboembolism. The effect of timing and duration of testosterone use on the risk of venous thromboembolism was not studied and may explain some of these contradictory findings. What are the main findings?

Response: Starting testosterone treatment is associated with an increased risk of serious blood clots (known as venous thromboembolism or VTE) that peaks within six months and declines gradually thereafter.

In the first six months of testosterone treatment, there is a 63% increased risk of venous thromboembolism among current testosterone users compared with no testosterone treatment, corresponding to 1 additional venous thromboembolism per 1000 person-years of testosterone use. The risk declines substantially after more than six months’ treatment and after treatment stopped. What should readers take away from your report?

Response: That the use of testosterone, especially in middle-aged and older men without pathological hypogonadism who may have other cardiovascular risks, may encounter a transient risk of venous thromboembolism when starting testosterone treatment. What recommendations do you have for future research as a result of this study?

Response: Future research is needed to confirm this temporal increase in the risk of venous thromboembolism, to investigate the risk in first time testosterone users and according to the indication for starting testosterone treatment. Is there anything else you would like to add?

Response: This is an observational study so no firm conclusions can be drawn about cause and effect. Thank you for your contribution to the community.


Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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Last Updated on December 4, 2016 by Marie Benz MD FAAD