LAS VEGAS – Analysis of data from a low testosterone therapy company showed that the treatment was not associated with higher risk of myocardial infarction and stroke in men, and it may have played a protective role.
The authors of the unpublished study analyzed 20,000 patient records, and when they compared the data with two community data sets, they found that the study’s patient group had seven and nine times lower risk of developing MI and strokes, respectively. Researchers said they found no evidence of worsening of preexisting MI or strokes in the study group.
The findings clash with what two recent studies found – one published in JAMA and the other in PLoS One – which was that testosterone therapy increased the risk of MI and stroke in men, prompting the Food and Drug Administration to reassess the safety of the approved treatments.
Meanwhile, this is not the first time that an observational study has shown a cardioprotective role for testosterone therapy in men.
“I don’t think this study adds much to the studies that have already been done,” said Dr. Bradley D. Anawalt, chief of medicine at the University of Washington Medical Center, Seattle, and chairman of Hormone Health Network at the Endocrine Society.
Dr. Aaron I. Vinik, Murray Waitzer Endowed Chair for Diabetes Research at Eastern Virginia Medical School, Norfolk, said that he wasn’t sure what could be concluded from the study. “It’s not prospective, it’s not blinded, there’s no control group, and it’s an observational study all over again.”
The one thing all experts, including the study authors, agree on is that there’s a need for a prospective randomized, controlled trial to prove or disprove a cause and effect relationship between testosterone therapy and risk of cardiovascular disease in men.
Dr. Robert Tan led the Low T Center study and presented the results on May 16 at the annual meeting of the American Association of Clinical Endocrinologists. He said he was an independent contractor for the company.
He conducted a cross-sectional analysis of the data from the electronic health records of 40 Low T Centers across the United States, selecting patients who had MI and stroke before and after testosterone therapy, between 2009 and 2014. The Low T Centers, which solely treat men with low testosterone, require regular 2-week monitoring of patients for safety and efficacy of the therapy.
There were four nonfatal MIs and two probable fatal MIs. The rate of new MI was 30/100,000 patients. Forty-six patients had MI before therapy and none had adverse outcomes after testosterone therapy, he reported.
Two patients had strokes, and the rate of new stroke was 10/100,000 patients. Twelve patients had a stroke before therapy, and there were no adverse outcomes after therapy, according to the findings.
For comparison, Dr. Tan used the closest available data sets, from Kaiser Permanente for MI (208/100,000) and Northern Manhattan Registry for stroke (93/100,000). The rate ratios showed that the patients in the study group were seven times less likely to have a myocardial infarction, and nine times less likely to have a stroke.
So why the difference?
“Maybe it’s not so much the drug, but maybe it’s the way the medication is given,” and is monitored, speculated Dr. Tan, also of the University of Texas, Houston. In addition, patients treated at Low T Centers were younger than 65 years, and excluded the older and sicker Medicare population.
Dr. Anawalt raised concerns about the fact that the analysis was done on a patient population treated at a company that has built a business model around treating men with low testosterone. He also said that the comparison groups — Kaiser Permanente and Northern Manhattan Registry — weren’t quite comparable.
He said that physicians should continue to carefully monitor their patients to avoid excessive dosage or erythrocytosis; know that in men with clearly established hypogonadism, it is safe to assume that benefits of testosterone therapy outweigh the risks; and be cautious when prescribing testosterone in men with borderline low testosterone, particularly in older men.
The findings highlight the fact that there are still many questions left to be answered, and this is just a glimpse into how much there is left to be learned about the effect of testosterone therapy on men’s cardiovascular health, Dr. Tan said.
Dr. Tan was an independent contractor for Low T Center. Dr. Anawalt and Dr. Vinik had no disclosures.