Prevalence of and Risk Factors for Low Free Testosterone Levels in Japanese Men with Well-controlled Human Immunodeficiency Virus Infection

Abstract

Background: The change in the prevalence of hypogonadism with age in men with human immunodeficiency virus (HIV) infection is subject to debate.

Objective: To address this issue, we diagnosed hypogonadism based on serum levels of free testosterone (fTST) rather than total testosterone which is thought to be an inaccurate indicator. We also determined the relationship between age and fTST levels and identified risk factors for hypogonadism in men with HIV infection.

Methods: We retrospectively reviewed fTST levels and associated clinical factors in 71 wellcontrolled HIV-infected men who were treated at Teikyo University Hospital between April 2015 and March 2016 and who had data available on serum fTST levels, measured >6 months after starting antiretroviral therapy. fTST was measured using radioimmunoassay on blood samples collected in the morning. Risk factors for hypogonadism were identified using Welch's t-test and multiple regression analysis.

Results: The men had a mean (± standard deviation) age of 47.4 ± 13.6 years, and mean (± standard deviation) serum fTST level of 13.0 ± 6.1 pg/mL. Fifteen (21.1%) men had hypogonadism based on a fTST <8.5 pg/mL. Serum fTST levels significantly decreased with age (-0.216 pg/mL/year). Older age and low hemoglobin levels were identified as risk factors for hypogonadism.

Conclusion: The men in the study experienced a more rapid decline in fTST levels with age than men in the general population (-0.161 pg/mL/year). Serum fTST levels in men with HIV infection should be monitored, especially in older men and those with low hemoglobin levels.

Keywords: HIV; ageing; free testosterone; hemoglobin; hypogonadism; radioimmunoassay.