Comparison of the Uroflowmetry Parameter Results Between Transgender Males Undergoing Gender-Affirming Hormone Therapy and Age-Matched Cisgender Females: Preliminary Data

Purpose: Gender-affirming hormone therapy (GHT) using testosterone is administered to transgender males. Although various effects caused by hormonal therapy have been reported, those on lower urinary tract function have remained unclear. The present study compared the uroflowmetry (UFM) parameter results between transgender males and age-matched cisgender females. Methods: A total of 26 transgender males who received GHT for longer than 1 year and the same number of age-matched cisgender females were enrolled. The UFM parameter results and postvoid residual urine volume (PVR) were compared between groups. Results: The median age at enrollment was 31.5 years, and the median duration of hormonal therapy was 2.7 years. There was no significant difference in the maximum flow rate or average flow rate between groups, whereas the mean voided volume (VV) (370±168 vs. 252±73 mL, p <0.001) and PVR (57.3±39.5 vs. 19.4±30.5 mL, p <0.001) were significantly greater in the transgender male group than those in the cisgender female group. Conclusion: The VV on UFM and postvoided residual urine volume in the transgender males who received GHT for >1 year were significantly increased compared with age-matched cisgender females.