therapy – widely advertised as a way to help men improve a
low sex drive and reclaim diminished energy – might raise the risk of heart
attack, according to new research.
The increased risk was found in men younger than 65 with a history of heart
disease, and in older men even if they didn't have a history of the disease. In
both groups, heart attack risk doubled in the 90 days after the men began
testosterone therapy, said researcher William Finkle, CEO of Consolidated
Research, in Los Angeles.
"It was more or less the same increase in risk," Finkle said.
Testosterone therapy typically is given in gel, patch or injection form, and
is widely promoted in television advertisements about "low T".
Although the treatment risk to men over 65 has been documented in previous
research, Finkle said, the new study is believed to be the first to look at men
Testosterone clinical trial
The study, published online in the journal PLoS One, was conducted by
a research team that included experts from Consolidated Research, the US
National Cancer Institute and the University of California, Los Angeles.
It was triggered by a 2010 report in the New England Journal of Medicine,
Finkle said. In that study, a clinical trial of testosterone gel in men over 65
was halted early after an increase in heart attacks and other heart problems
occurred in the group using the testosterone supplements.
testosterone supplements help patients with heart failure
Finkle's team used data from Truven Health Analytics, which gathers
nationwide information on patient care. The researchers looked at the medical
records of nearly 56 000 men who had been prescribed testosterone therapy --
more than 48 000 of whom were under age 65.
"We identified the [timing of the] first prescription and followed them
for 90 days," Finkle said. The risk for heart attack doubled in that
90-day period for men over 65 and those under 65 with a history of heart
disease, the researchers found.
Two-fold risk increase
When they continued to follow the men for another 90 days, the researchers
said, the risk declined to the level it was at the study's start for men who
did not refill their initial prescription.
Even though the two-fold increase in risk in younger men was seen only in
those with a history of heart disease, Finkle said he's uncertain of the
therapy's safety in younger, healthy men.
"We don't have enough evidence to say testosterone supplements in men
under age 65 without heart disease are safe," he said.
Although the researchers found an association between testosterone therapy
and increased risk of heart attack, the study did not prove a cause-and-effect
The study authors also did not examine the explanation for the link, but
Finkle said it could be tied to the effect of testosterone in blood.
"The theory is that testosterone most likely promotes clotting,"
he said. In older men who tend to have thinner vessels, that clotting could
cause problems, he said.
The supplements might also increase men's circulating estrogen, the
researchers said. Oestrogen therapy has been linked to an increase in heart
troubles in both men and women.
AbbVie and Actavis, the makers of testosterone therapies, did not respond to
requests for comment on the study.
But one expert not involved in the research expressed scepticism, citing
flaws in the study design.
"Based on the best available data, testosterone replacement still
appears to be safe ... for properly selected patients," said Dr Ryan
Terlecki, director of the Men's Health Clinic at the Wake Forest Baptist
Among the flaws in the study, Terlecki said, was the use of information
obtained from medical claims data, which makes it uncertain which men actually
used the testosterone.
"This is important since compliance can be poor, especially with
topical formulations," he said. Terlecki reported that he previously
worked as a consultant for Auxilium, which makes testosterone therapy.
The researchers did not have information on why the testosterone therapy was
prescribed, so it could have been prescribed inappropriately, Terlecki said. He
also cited other data that has linked low testosterone – not testosterone
therapy – to an increased risk of heart disease.
Men who are discussing testosterone therapy with their doctors "should
add the risk of heart attack to the discussion of the risks and benefits of
testosterone," Finkle said.
Terlecki said men who have a lack of energy should first see their doctor
and ask about screening for depression and other conditions – such as thyroid
disease or B12
deficiency – that could also be the cause.
Testosterone therapy is marketed so successfully that the independent
medicine website Drugs.com reported that sales of Androgel exceeded sales of
Viagra in 2013, according to UCLA researchers.
therapy ups risk of bad outcomes in older men