Testosterone Replacement Therapy Can Improve a Biomarker of Liver Fibrosis in Hypogonadal Men: A Subanalysis of a Prospective Randomized Controlled Study in Japan (EARTH Study).

Purpose: We investigated the effects of testosterone replacement therapy (TRT) on the Fibrosis-4 (FIB-4) index among hypogonadal patients who were extracted from a randomized controlled study in Japan (the EARTH study).

Materials And Methods: Data of 186 patients (88 in the TRT group; 98 in the control group) were collected. The patients in the TRT group received intramuscular administration of testosterone enanthate (250 mg) every 4 weeks for 12 months. The patients' background information such as current medical history and lifestyle habits were collected. Waist circumference, body mass index, and body fat volume were measured at baseline and 12-month visit. Fasting blood sugar (FBS), hemoglobin A1c, total cholesterol, triglyceride (TG), and high-density lipoprotein cholesterol levels were collected at baseline and 12-month visit. The FIB-4 index was calculated according to age, aspartate aminotransferase, alanine transaminase, and platelet count.

Results: Except for serum FBS values, most of baseline characteristics were comparable between the TRT and control groups. When comparing the changes of each variable from baseline at 12-month visit in both groups, significant differences were found in waist circumference (p=0.00248), fat volume (p=0.00812), and platelet counts (p=0.0478), whereas a FIB-4 index did not change. On the contrary, in a subanalysis including only patients with a FIB-4 index ≥1.30 at baseline, a significant difference in a FIB-4 index (-0.10±0.39 0.04±0.44; p=0.0311) was observed with significant decreases in waist circumference, body fat volume, and TG levels, and an increase in platelet counts. The FIB-4 index was significantly decreased by TRT from 1.98±0.52 to 1.87±0.60 (p=0.0277).

Conclusions: TRT for 12 months improved the FIB-4 index among hypogonadal men with a higher baseline FIB-4 index.