The association of free testosterone levels with coronavirus disease 2019

Angiotensin-converting enzyme 2 and transmembrane protease serine 2 are critical factors of virus transmission. Expression of angiotensin-converting enzyme 2 is highest in testes, and testicular function and testosterone levels were affected by coronavirus disease 2019. Low testosterone levels are related to infections, especially respiratory tract infections, and could worsen clinical conditions by exacerbating cytokine storms and increasing pro-inflammatory cytokines.

We aimed to evaluate the acute and chronic effects of coronavirus disease 2019 on gonadal functions. Our second aim was to detect the relationship between free testosterone levels and disease prognosis and determine the impact of low-free testosterone on admission to the intensive care unit.

Eighty-one patients with reverse-transcription polymerase chain reaction-confirmed coronavirus disease 2019 were enrolled. Twenty-nine patients were assessed again for 6 months post-coronavirus disease 2019 follow-up, and seven of them had a semen analysis. Serum follicle-stimulating hormone, luteinizing hormone, sex hormone-binding globulin, and total testosterone levels were measured.

In this observational study, 71.6% (n = 58) of patients had low free testosterone levels at baseline, in which 69% were considered secondary hypogonadism. A longer length of hospitalization and increased inflammatory markers (d-dimer, high-sensitive C-reactive protein, and procalcitonin) were detected in the low-free testosterone group. Follicle-stimulating hormone, total, free, and bioavailable testosterone levels were lower in patients who required admission to the intensive care unit. Free testosterone levels were inversely correlated with the length of hospitalization and prognostic disease factors. Oligozoospermia and impaired progressive motility were present in 42.8% (3/7) of the patients. In 6 months post-coronavirus disease 2019 follow-up, out of 29 patients, 48.2% still had low testosterone levels.

A high rate of hypogonadism (71.6%) was found, especially secondary hypogonadism, and about half of the patients had hypogonadism in the sixth months' follow-up. Low free testosterone levels were correlated with inflammatory parameters, and it is related to the intensive care unit admission. Studies with long-term follow-up data in larger groups are needed to determine persistent hypogonadism and impaired spermatogenesis.