Risk benefit favors younger men, potential for harm increases with age
Loss of libido or desire for intimacy is a common problem as a man ages. A recently published paper shows that testosterone therapy improves sexual desire and activity across almost all domains in symptomatic older men manifesting with low libido and low testosterone levels. This positive effect has been attributed to the changes in both testosterone and estradiol levels.
This was the finding of a research, published in the June 29 issue of Journal of Clinical Endocrinology and Metabolism. The paper was an additional analysis of data from the Sexual Function Trial, and was part of a coordinated set of seven double-blind, placebo-controlled studies in the Testosterone Trial.
In the Sexual Function Trial, it was shown that testosterone therapy was associated with a significant increase in sexual activity, indicated by the Psychosexual Daily Questionnaire (PDQ) score. Sexual desire and erectile function were likewise improved.
According to Glenn R. Cunningham, MD, of Baylor College of Medicine and Baylor St. Luke’s Medical Center in Houston, Texas, this study more thoroughly indicates that testosterone therapy is really beneficial, as it improved 10 of the 12 domains of sexual activity on the PDQ, especially on measures associated with libido.
In an interview with Medscape Medical News, Dr. Cunningham said that their study showed that even in older men who are testosterone deficient and who have decreased libido, “testosterone treatment can be beneficial in terms of sexual function and not only in terms of libido but also in terms of erectile function and sexual activity.”
He cautioned however that the physician weighs the risks against the benefits. The patient’s age also has to be considered in treating men with symptoms and low testosterone levels. The risk-benefit ratio is more favorable in younger men. “As you get into middle age and older, then there’s a greater potential for risk,” Dr. Cunningham said.
Among the risks noted by Dr. Cunningham with testosterone therapy are the increase for the potential for an occult prostate cancer to become a clinical prostate cancer and the potential increase in cardiovascular risk.
“Neither of those are proven, but because we know androgens have effect on parameters that are relevant here, we need to have clinical-trial data to resolve that,” Dr, Cunningham was quoted.
The study enrolled 470 men aged = 65 years who had low libido, an average testosterone level of <275 ng/dL, and a partner willing to have sexual intercourse at least twice a month.
The men were randomized to either a 1 percent testosterone gel at an initial dose of 5 gram daily or a placebo gel for one year. The researchers assessed sexual function using the PDQ, the Derogatis Interview for Sexual Function, and the International Index of Erectile Function every three months.
More than 60 percent of the study subjects were obese, with around a third of them having diabetes, and 70 percent having hypertension. Only 11 percent were using a phosphodiesterase type 5 inhibitor for erectile dysfunction.
Testosterone treatment significantly increased serum total and free testosterone and estradiol levels up to the mid-normal range for healthy men aged 19 to 40 years, with no effect in the placebo group.
Participants in the testosterone group showed significant improvements vs placebo on 10 of the 12 domains of sexual activity on the PDQ: sexual daydreams; anticipation of sex; sexual interaction with a partner; flirting by subject; orgasm; ejaculation; intercourse; masturbation; spontaneous erection at night; and sexual arousal erection (P < .001 to .026). The treatment effect size ranged from 0.02 for intercourse to 0.10 for sexual daydreams.
No significant improvements attributable to testosterone therapy were noted on the domains of flirting by others and spontaneous erections by day. Examples of a few nominally significant interactions between some baseline characteristics and the effect of testosterone therapy were: increased alcohol intake associated with a greater effect of testosterone on sexual desire and activity; history of stroke and coronary artery disease and higher prostate symptom and Positive and Negative Affect Scale scores were associated with a lower effect of testosterone.
The Testosterone Trial was supported by a grant from the National Institute on Aging and National Institutes of Health, supplemented by funds from the National Heart, Lung, and Blood Institute, National Institute of Neurological Diseases and Stroke, and National Institute of Child Health and Human Development. With J Clin Endo and Metab, Medscape Medical News reports
Vital Signs July 1-31 2016