Impact of Growth Hormone Secretagogues On Anthropomorphic Parameters in Men Using Body Composition Analysis http://www.jurology.com/article/S0022-5347(18)42174-X/fulltext INTRODUCTION AND OBJECTIVES - The strict diagnostic criteria imposed by the FDA for prescribing exogenous human growth hormone (hGH) have significantly restricted its use. GH secretagogues (GHS) represent a new and scientifically unstudied alternative to hGH while minimizing unwanted side effects (Table 1). Clinical data on the effect of GHS on body composition is limited. Here we determine the impact of GHS on anthropomorphic parameters in men using impedance based body composition analysis. METHODS - Men presenting to a single andrology clinic from 2015 to 2017 were evaluated while on therapy using an InBody (IB) impedance-based body composition analysis at baseline and at follow-up visits at least 3 months apart. The study cohort was comprised of hypogonadal men on testosterone therapy (TTh) and prescriptions for any GHS used were recorded. Exercise intensity was measured using the validated Rapid Assessment of Physical Activity (RAPA) questionnaire. Multivariate analysis was used to determine changes in body composition over 6 months controlling for age, RAPA score, baseline body composition, medication type and duration of use. RESULTS - 145 men underwent IB analysis with an average age of 37.3±8.3 years, RAPA score 6±1.4 and time between sequential IB analyses of 7.6 months. Only the use of ibutamoren was associated with a statistically significant change in baseline body composition: a 9.7% increase in lean body mass (LBM), a 6.5% increase in skeletal muscle mass (SMM), and a 9.7% decrease in body fat mass (BFM) (all p<0.001). When baseline percent LBM, SMM and BFM were stratified by quartile, men with the greatest increase in LBM and SMM on ibutamoren therapy over time were in the lowest initial quartile (least muscle mass) (p<0.05). Men with the greatest decrease in BFM on ibutamoren therapy over time were in the highest initial quartile (highest fat mass) (p<0.05). Age and RAPA scores were not associated with changes in body composition. CONCLUSIONS - In this novel analysis of GHS, only ibutamoren showed significantly positive effects on LBM, BFM and SMM that were more pronounced in men with the most abnormal baseline levels. Realizing the current health burden of obesity in hypogonadal men, the use of GHS may add significant therapeutic benefit.