Meta-analysis of Results of Testosterone Therapy on Sexual Function Based on International Index of Erectile Function Scores

Abstract

Context: The interpretation of available clinical evidence related to the effect of testosterone (T) treatment (TTh) on sexual function has been inconsistent, in part due to the use of different and self-reported measures to assess outcomes. The International Index of Erectile Function (IIEF) is the most frequently used validated tool to assess male sexual function.

Objective: To perform a meta-analysis of available data evaluating the effect of TTh on male sexual function using IIEF as the primary outcome.

Evidence acquisition: An extensive Medline, Embase, and Cochrane search was performed including all placebo-controlled randomized clinical trials enrolling men comparing the effect of TTh on sexual function.

Evidence synthesis: Out of 137 retrieved articles, 14 were included in the study enrolling 2298 participants, with a mean follow-up of 40.1 wk and mean age of 60.2±6.5 yr. Using IIEF-erectile function domain (IIEF-EFD) as the outcome, we found that TTh significantly improved erectile function compared with placebo (mean difference=2.31 [1.41;3.22] IIEF-EFD score, p<0.0001). Patients with more severe hypogonadism (total T<8 nmol/l) reported greater changes in final IIEF-EFD score when compared with those with a milder T deficiency (total T<12 nmol/l; 1.47 [0.90;2.03] and 2.95 [1.86;4.03] for total T<12 nmol/l and <8 nmol/l, respectively, Q=5.61, p=0.02). The magnitude of the effect was lower in the presence of metabolic derangements, such as diabetes and obesity. Other aspects of sexual function, as evaluated by IIEF subdomains, were also improved with TTh including libido, intercourse satisfaction, orgasm, and overall sexual satisfaction.

Conclusions: TTh significantly improves erectile function and other sexual parameters as measured by IIEF in hypogonadal men. These results argue that sexual dysfunction should be considered a hallmark manifestation of T deficiency, since those symptoms can be significantly improved with normalization of serum T. In addition, these results suggest that TTh alone may be considered a reasonable treatment for hypogonadal men with milder degrees of erectile dysfunction, whereas the addition of other treatments, such as phosphodiesterase type 5 inhibitors, may be more appropriate for men with more severe erectile dysfunction.

Patient summary: We investigated the effect of testosterone treatment on sexual function by performing a meta-analysis of all available studies that used the most frequently used assessment tool, the International Index of Erectile Function. We found that testosterone treatment significantly improves erectile dysfunction, as well as other aspects of sexual function, in men with testosterone deficiency. This treatment may be all that is required for hypogonadal men with milder erectile dysfunction; however, additional treatments may be necessary in more severe cases.

Keywords: Ejaculation; Erectile dysfunction; Erection; International Index of Erectile Function; Libido; Orgasm; Sexual function; Testosterone.