Effects of Testosterone Treatment in Older Men

Abstract

Background: Serum testosterone concentrations decrease as men age, but benefits of raising testosterone levels in older men have not been established.

Methods: We assigned 790 men 65 years of age or older with a serum testosterone concentration of less than 275 ng per deciliter and symptoms suggesting hypoandrogenism to receive either testosterone gel or placebo gel for 1 year. Each man participated in one or more of three trials--the Sexual Function Trial, the Physical Function Trial, and the Vitality Trial. The primary outcome of each of the individual trials was also evaluated in all participants.

Results: Testosterone treatment increased serum testosterone levels to the mid-normal range for men 19 to 40 years of age. The increase in testosterone levels was associated with significantly increased sexual activity, as assessed by the Psychosexual Daily Questionnaire (P<0.001), as well as significantly increased sexual desire and erectile function. The percentage of men who had an increase of at least 50 m in the 6-minute walking distance did not differ significantly between the two study groups in the Physical Function Trial but did differ significantly when men in all three trials were included (20.5% of men who received testosterone vs. 12.6% of men who received placebo, P=0.003). Testosterone had no significant benefit with respect to vitality, as assessed by the Functional Assessment of Chronic Illness Therapy-Fatigue scale, but men who received testosterone reported slightly better mood and lower severity of depressive symptoms than those who received placebo. The rates of adverse events were similar in the two groups.

Conclusions: In symptomatic men 65 years of age or older, raising testosterone concentrations for 1 year from moderately low to the mid-normal range for men 19 to 40 years of age had a moderate benefit with respect to sexual function and some benefit with respect to mood and depressive symptoms but no benefit with respect to vitality or walking distance. The number of participants was too few to draw conclusions about the risks of testosterone treatment. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT00799617.).

Figure 1. Primary Outcomes in the Three Main Trials of the Testosterone Trials

The primary outcome of the Sexual Function Trial (Panel A) was the change from baseline in the score for sexual activity (question 4) on the Psychosexual Daily Questionnaire (PDQ-Q4; range, 0 to 12, with higher scores indicating more activity). The primary outcome of the Physical Function Trial (Panel B) was the percentage of men who had an increase of at least 50 m in the distance walked during the 6-minute walk test. The primary outcome of the Vitality Trial (Panel C) was the percentage of men who had an increase of at least 4 points in the score on the Functional Assessment of Chronic Illness Therapy (FACIT)–Fatigue scale (range, 0 to 52, with higher scores indicating less fatigue). P values were calculated with the use of a linear random-effects model for sexual activity and logistic random-effects models for walking ability and vitality. The I bars represent standard deviations.