Data from these three trials show that testosterone supplementation yields some benefits, but they were modest, tended to wane toward the end of the year of treatment, and were not as robust as those reported with use of phosphodiesterase type 5 inhibitors. These results might be insufficient to support a decision to initiate testosterone therapy in symptomatic older men.
Although no major toxicities were apparent and effects on hemoglobin and prostate-specific antigen levels appeared to be minor, larger and more extended trials are needed to establish the adverse effects of testosterone supplementation, especially regarding prostate and cardiovascular health.
In addition, the fact that only 1.5% of the more than 51,000 men who were screened were actually enrolled in these studies clearly limits the generalizability of their conclusions. Most testosterone prescriptions are written for middle-aged men, but we cannot assume that the benefits, lack of benefits, and adverse-event profiles of these study participants apply to younger men, those with higher testosterone levels, or those with other demographic and clinical characteristics.
Dr. Eric S. Orwoll is in the department of medicine at Oregon Health and Science University, Portland. He reported receiving grants and personal fees from Eli Lilly, Merck, and Amgen. Dr. Orwoll made these remarks in an editorial accompanying Dr. Snyder’s report (New Engl J Med. 2016 Feb 18. doi: 10.1056/NEJMe1600196).
