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14 July 2014

Effects of testosterone deficiency on body composition, strength and sexual function in men, and the tolerability of long-acting testosterone undecanoate in daily clinical practice

Effects of testosterone deficiency on body composition, strength and sexual function in men, and the tolerability of long-acting testosterone undecanoate in daily clinical practice

Gonadal steroids and body composition, strength, and sexual function in men. Finkelstein JS, Lee H, Burnett-Bowie S-A, et al. N Engl J Med 2013;369:1011−22.

IPASS: A study on the tolerability and effectiveness of injectable testosterone undecanoate for the treatment of male hypogonadism in a worldwide sample of 1,438 men. Zitzmann M, Mattern A, Hanisch J, et al. J Sex Med 2013;10:579−88.

This editorial includes summaries of two studies: the first is an experimental study in men looking at the effects of testosterone deficiency on body composition, strength and sexual function; the second is a post-observational surveillance study (IPASS) investigating the tolerability of long-acting testosterone undecanoate (TU) in men with testosterone deficiency syndrome (hypogonadism) in a clinical practice setting.

The classification of low testosterone levels – at least 2 standard deviations below the mean value for healthy young adults – does not take into account the physiological consequences of various testosterone levels. In particular the implications of the concomitant decline in serum levels of estradiol, a metabolite of testosterone, are generally not considered. This summary describes the results from an experimental study in two cohorts of healthy men, both of whom received goserelin acetate to suppress endogenous testosterone and estradiol (Cohort 1; n=198; Cohort 2; n=202). Participants were randomly assigned to receive placebo, 1.25 g, 2.5 g, 5 g or 10 g of testosterone gel daily for 16 weeks. In order to differentiate between the effects of testosterone and estradiol, participants in Cohort 2 also received anastrozole 1 mg daily, an aromatase inhibitor, to block the conversion of testosterone to estradiol. The primary outcome variables were changes in percentage of body fat and total-body lean mass. Changes in subcutaneous- and intraabdominal-fat areas, thigh-muscle area and leg-press strength, and sexual function were also assessed.

The prospective, observational IPASS was conducted in 23 countries in Europe, Asia, Latin America, and Australia and investigated the safety and efficacy of intramuscular injections of TU in men with hypogonadism in a “real-life setting”.
A total of 1493 men (age 49.2 ± 13.9 years; 72.5% Caucasian) with hypogonadism were enrolled into the study to receive up to five injections of TU over an observation period of 9–12 months. The first and second injections were given at intervals of 6–10 weeks, and subsequent injections at intervals of 12 ± 2 weeks. Patients subjectively assessed the intensity of hypogonadism-related symptoms at each study visit, and at the end of the treatment period gave a rating of overall tolerability. Laboratory measurements, including prostate-specific antigen (PSA), hemoglobin, hematocrit, and lipid profiles, as well as digital rectal examination were also assessed at each study visit. At baseline and the time of the fifth injection a total of 1438 and 1140 men were evaluable, respectively. At baseline, body weight was 86.8 ± 17.6 kg, waist circumference 99.5 ± 15.25 cm and serum testosterone 9.6 ± 7.5 nmol/L.The summary of this study reports the results for the safety, anthropometric and sexual function measurements.



Key Points

  • The randomized controlled study showed that there is considerable variation in the dose of testosterone required to prevent adverse changes in body composition, strength and sexual function

    • Only the highest dose of testosterone (10 g) achieved levels sufficient to reduce body fat
  • In this experimental study, administration of an aromatase inhibitor allowed the effects of testosterone and estrogen to be distinguished

    • Decreases in total-body lean mass, thigh-muscle area and leg-press strength were attributed to testosterone deficiency
    • Estrogen deficiency played a role in the increases in body fat
  • Both testosterone and estradiol are needed for maintenance of normal sexual function
  • Interpretation and treatment of hypogonadism in men should be individualized
  • In IPASS, TU was well tolerated in men with hypogonadism, and ADRs were rare (5.8%)
  • Increases in hematocrit and PSA, and injection site pain were the most common ADRs occurring in <1% of patients
  • Treatment-related ADRs lead to discontinuation in 31 men
  • Marked improvements in overall levels of sexual desire/libido were observed with TU
  • At the fifth injection of TU there was a significant decrease in waist circumference (p≤0.003), and a slight decrease in body weight

14 July 2014

Effects of testosterone deficiency on body composition, strength and sexual function in men

Effects of testosterone deficiency on body composition, strength and sexual function in men
This paper presents the findings from a study that looked at the effects of testosterone on body fat, lean mass, thigh-muscle area and strength, and sexual function in healthy men who had their testosterone levels experimentally reduced. As the majority of estradiol (a form of estrogen) is obtained from testosterone, the concomitant decrease in estradiol was also investigated and the effects differentiated from those of testosterone.
Last updated: 2018
L.ZA.MKT.GM.10.2016.1381