What is a predictive factor of the efficacy of testosterone replacement for late-onset hypogonadism?

Abstract

ABSTRACT Introduction Testosterone replacement therapy (TRT) is a worldwide first-choice method of treatment for late-onset hypogonadism (LOH). In the diagnosis of LOH in Japan, we use 8.5 pg/mL of serum free-testosterone (FT) level measured by RIA as a lower limit. Objective The objective of this study is to determine the predictors of the TRT efficacy for LOH. Methods A total of 56 patients who attended our men's health clinic between August 2002 and June 2021 with the data available before and after TRT were enrolled into this study. These patients were divided into responders to TRT (Group 1, n=45, 80%) and non-responders to TRT (Group 2, n=11, 20%) according to clinical response including patient's satisfaction. Evaluated parameters obtained before TRT were following: age, BMI, aging males symptoms scale (AMS), sexual health inventory for men (SHIM), serum luteinizing hormone (LH), follicular stimulating hormone (FSH), testosterone (T), FT, prolactin (PRL), estradiol (E2) and T/E ratio. For statistical analysis, we used a multivariable logistic regression model. Results Univariate analysis revealed PRL (OR 0.96; 95% CI 0.93-0.99, P<0.03), E2 (OR 0.87; 95% CI 0.77-0.98, P<0.02), T/E (OR 1.13; 95% CI 1.01-1.27, P<0.04) as predictive factors. Then we carried out multivariate analyses of these factors and determined T/E ratio as an independent predictive factor (OR 1.16; 95% CI 1.04-1.29, P<0.01). Conclusion This study suggested that low value of T/E ratio might predict the low response to TRT. Although further study with a larger number of patients is necessary, we propose the measurement of serum E2 level as well as testosterone level before TRT. Disclosure Work supported by industry: no.