You may have seen one of the many advertisements geared toward men asking if they suffer from "low T" — low testosterone levels that, according to the ads, can result in lost sex drive, diminished energy and moodiness. The answer, they suggest, may be as simple as applying testosterone through a gel or patch.
So successful has the marketing for this testosterone therapy been that, according to Drugs.com, an independent medicine website, sales of the testosterone gel Androgel in 2013 exceeded sales of Viagra.
Now, a new joint study by UCLA, the National Institutes of Health and Consolidated Research Inc., has shown there is a twofold increase in the risk of a heart attack shortly after beginning testosterone therapy among men under 65 who have a history of heart disease. Further, the study confirmed earlier studies that found a twofold increase in heart attack risk shortly after treatment began in men older than 65.
The study, the largest to date examining heart disease in men using testosterone supplements, appears in the Jan. 29 online edition of the journal PLOS ONE.
The research was prompted by three small, earlier studies that raised concerns about possible adverse cardiovascular outcomes associated with testosterone therapy. These included a randomized clinical trial of men older than 65, which was reported in the New England Journal of Medicine and was stopped in 2010 due to a variety of cardiovascular events.
"We decided to investigate cardiovascular risks of this therapy in a large health care database since these previous studies were modest in size and only focused on men 65 and older," said the study's senior author, Sander Greenland, a professor of epidemiology at the UCLA Fielding School of Public Health and a professor of statistics in the UCLA College of Letters and Science. "Our study allowed us to examine cardiovascular risk in men under the age of 65 and to replicate the findings in men over 65."
Greenland and his colleagues used data from Truven Health Analytics, which aggregates information on patient care. They examined the health care records of 55,593 men who had been prescribed testosterone therapy — 48,539 under the age of 65 and 7,054 who were 65 or older. Their research led to the finding of a twofold increase in men under 65 with heart disease and confirmed the earlier findings of a twofold increase in men over 65 with or without heart disease.
"The extensive and rapidly increasing use of testosterone treatment and the evidence of risk of heart attack underscore the urgency of further large studies of the risks and the benefits of this treatment," Greenland said. "Patients and their physicians should discuss the risk of heart attacks when considering testosterone therapy."
Other authors on the study included William D. Finkle (first author), Gregory K. Ridgeway, John L. Adams and Melissa A. Frasco, of Consolidated Research Inc., and Michael B. Cook, Joseph F. Fraumeni Jr. and Robert N. Hoover, of the NIH. Funding for the study was provided by the NIH.