Predictive factors for efficacy of testosterone replacement therapy for late-onset hypogonadism in Japanese men: a preliminary report.

The majority of LOH patients responded to TRT, with 80.4% classified as responders and 19.6% as nonresponders.

• 56 total patients were enrolled from November 2003 to June 2021
• Group 1 (responders): n = 45, accounting for 80.4%
• Group 2 (nonresponders): n = 11, accounting for 19.6%
• Classification was based on clinical response to TRT including patient satisfaction

Univariate analysis identified prolactin (PRL), estradiol (E2), and testosterone/estradiol (T/E2) ratio as predictive factors for TRT efficacy.

• PRL: OR 0.9624, 95% CI 0.9316–0.9943, P < 0.05
• E2: OR 0.8692, 95% CI 0.7745–0.9754, P < 0.05
• T/E2 ratio: OR 1.1312, 95% CI 1.0106–1.2661, P < 0.05
• Other factors assessed included age, BMI, aging males' symptoms score, SHIM, LH, FSH, testosterone, free testosterone, and prolactin

Multivariate analysis identified the T/E2 ratio as an independent predictive factor for TRT efficacy.

• T/E2 ratio OR: 1.1593, 95% CI 1.0438–1.2875, P < 0.01
• A multivariable logistic regression model was used for statistical analysis
• PRL and E2 did not remain significant as independent predictors in multivariate analysis

A T/E2 ratio threshold of 17.3 was identified to predict nonresponders to TRT.

• Threshold was determined using receiver-operating characteristics (ROC) curve analysis
• A low value for T/E2 ratio was found to predict a reduced response to TRT
• The authors propose serum E2 and testosterone levels should be measured prior to performing TRT