No link exists between testosterone therapy and blood clots in veins, a new study shows.

The large comparative analysis, involving more than 30,000 commercially insured men, found that middle-aged and older men who receive testosterone therapy are not at increased risk of this illness.

Venous thromboembolism (VTE) is a disease in which blood clots form in the veins, causing blockages. The most typical forms of VTE are deep vein thrombosis, which occurs often in the legs, and pulmonary embolism, a clot in the lungs. After heart attack and stoke, VTE is the third most common cardiovascular illness.

Lead author Jacques Baillargeon, professor of epidemiology, said:

“In 2014, the Federal Drug Administration required manufacturers to add a warning about potential risks of VTE to the label of all approved testosterone products. The warning, however, is based primarily on post-marketing drug surveillance and case reports. To date, there have been no published comparative, large-scale studies examining the association of testosterone therapy and the risk of VTE.”

Due to conflicting evidence and the broad media attention it has received, there are many men with medically confirmed low testosterone who are fearful of testosterone therapy. There may also be physicians reluctant to prescribe testosterone therapy based on this conflicting information.

In a case-control study involving 30,572 men 40 years and older, researchers found that having a prescription for testosterone therapy was not associated with an increased risk of VTE.

Additionally, none of the specific routes of administration examined, topical creams, transdermal patches or intramuscular injections, were associated with an increased risk. There were no differences between men who received the therapy 15, 30 or 60 days before being diagnosed with VTE.

“It is important to acknowledge, for a man who has medically-diagnosed low testosterone, that there are clear risks to not receiving testosterone therapy, including osteoporosis, sexual dysfunction, increased amounts of fat tissue, decreased lean muscle mass, possible metabolic syndrome and cardiovascular disease,” said Baillargeon. “It’s also important to note that further research needs to be conducted to rigorously assess the long-term risks of testosterone therapy.”

Jacques Baillargeon, Randall J. Urban, Abraham Morgentaler, Charles J. Glueck, Gwen Baillargeon, Gulshan Sharma, Yong-Fang Kuo Risk of Venous Thromboembolism in Men Receiving Testosterone Therapy Mayo Clinic Proceedings DOI:

Photo: GEEKSTATS/flickr

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