Weather 
Interest in testosterone replacement therapy keeps climbing, and the TRAVERSE trial remains the largest randomized test of its cardiovascular safety. Here is what men considering treatment and their doctors need to know about the findings.
What Is the TRAVERSE Trial and Why Does It Matter?
The TRAVERSE trial is the largest randomized controlled study designed to test whether testosterone replacement therapy raises the risk of major heart problems in men with confirmed hypogonadism. Results were published in 2023 in the New England Journal of Medicine.
Researchers enrolled 5,246 men ages 45 to 80 who had preexisting cardiovascular disease or a high risk of it, symptoms of low testosterone and two fasting testosterone readings below 300 ng per deciliter. Participants received either daily transdermal 1.62 percent testosterone gel or placebo gel for a mean of 21.7 months, with mean follow-up of 33 months. The study was mandated after a 2015 FDA requirement that testosterone product makers investigate cardiovascular risk.
Does Testosterone Therapy Increase Heart Attack or Stroke Risk?
No. In TRAVERSE, testosterone gel was noninferior to placebo for the primary composite of cardiovascular death, nonfatal myocardial infarction and nonfatal stroke.
A primary event occurred in 182 patients (7.0 percent) receiving testosterone versus 190 patients (7.3 percent) on placebo, with a hazard ratio of 0.96 and a 95 percent confidence interval of 0.78 to 1.17. “These findings provide reassurance about the cardiovascular safety of testosterone therapy over the typical duration of treatment in men in whom it is indicated,” said coprincipal investigator A. Michael Lincoff, MD. He noted that years of conflicting evidence from small trials and observational studies had left the question unresolved until TRAVERSE was completed.
Who Was Included in the Traverse Testosterone Study?
TRAVERSE enrolled middle-aged and older men with symptoms of hypogonadism who met the same low-testosterone threshold used to confirm eligibility, all of whom had preexisting cardiovascular disease or elevated cardiovascular risk.
That population matters. The researchers stress the safety findings apply only to men who meet medical criteria for testosterone therapy, not to men obtaining it from “low T clinics” or providers who prescribe without a clear clinical indication. “This study should not be used as a justification for the widespread prescription of testosterone to aging men,” said study chair Steven Nissen, MD, chief academic officer of Cleveland Clinic’s Heart, Vascular & Thoracic Institute.
What Are the Risks of Testosterone Replacement Therapy?
Even with reassuring cardiovascular findings, TRAVERSE flagged higher rates of atrial fibrillation, acute kidney injury and pulmonary embolism in the testosterone group compared with placebo.
Pulmonary embolism occurred in 0.9 percent of testosterone patients versus 0.5 percent of placebo patients. Rasi Wickramasinghe, MD, PhD, FACC, chief of cardiology at Houston Methodist Sugar Land Hospital, told Cardiology Advisor that he thinks twice before prescribing testosterone in a man with prior venous thromboembolism or a known thrombophilia. He also cited observational data suggesting an increased atrial fibrillation risk of about 27 percent over five years in treated men. As Dr. Nissen put it, “This study shows that, for men with adrenogen deficiency in whom testosterone is clinically indicated, testosterone appears to be safe from a cardiovascular perspective, but it is not without adverse effects.”
What Does the Traverse Study Mean for Future Testosterone Treatment Decisions?
TRAVERSE sets a new baseline for how doctors weigh testosterone therapy in men with hypogonadism, but it does not settle every question about long-term use or specific patient subgroups.
Mohit Khera, MD, of Men’s Health Urology called the trial “a beacon for future research in testosterone replacement therapy and cardiovascular health,” pointing to the need for deeper study of the atrial fibrillation, kidney injury and pulmonary embolism signals. He urged individualized risk-benefit analyses to guide clinical decisions. The takeaway for patients, according to the researchers, is that testosterone replacement appears cardiovascular-safe when clinically indicated, provided prescribers screen for clot history and monitor for arrhythmia during therapy.
