Subclinical male hypogonadism

Introduction: The concept of subclinical or compensated male hypogonadism (SHG), characterized by increased gonadotropins and normal testosterone levels is emerging. However, its real clinical significance is still conflicting. The aim of the present study is to summarize and discuss the available evidence related to the possible definition of SHG and the possible advantages of testosterone replacement therapy (TRT). Evidence acquisition: A comprehensive systematic Medline, Embase and Cochrane search was performed. Publications from January 1, 1969 up to February 29th, 2020 were included. The search was restricted to English-language articles and studies of human participants. Evidence synthesis: Two main clinical forms of SHG can be described. The first identifies young patients who have a positive medical history for testis damage occurring before puberty onset. The second form can occur as a consequence of an age-dependent decline of T. Whereas the former can be the consequence of several congenital or acquired diseases, also possible causes of primary hypogonadism, the real significance of the latter is still debatable. Available evidence indicates that age-related SHG is quite a common phenomenon, occurring in 9.4% of aging men from the general population. Cross-sectional and longitudinal data have documented that it is associated with poor health and can be a sign of forthcoming increased cardiovascular mortality and morbidity. Conclusions: Although available evidence suggests that in aging populations SHG can be considered a particular condition associated with an increased CV risk, it is still unknown if treatment with T can improve any outcomes in these subjects. Hence, further interventional studies are advisable in order to better understand the characteristics of SHG and the possible advantages of an early TRT.