Impact of Transaffirmative Hormone Therapy on Hormonal and Metabolic Parameters in Chilean Transgender Individuals: 2-Year Follow-up.

UNLABELLED: Transgender individuals are becoming increasingly visible and have specific healthcare needs. There is very limited information regarding the metabolic effects of gender-affirming hormone therapy, particularly in Latin American populations. AIM: To evaluate the endocrine and metabolic effects of gender-affirming hormone therapies (GAHT) in transgender individuals in Chile, as well as their safety and achievement of treatment targets. METHODS: This ambispective observational cohort study assessed endocrine and metabolic laboratory parameters in transgender individuals over 18 years of age receiving masculinizing or feminizing GAHT over 24 months. RESULTS: 124 individuals met the inclusion criteria (58 transfeminine [TF], mean age 25 years, and 66 transmasculine [TM], mean age 22 years). TF participants had a mean height of 170 cm, weight of 72.9 kg, and BMI of 25 kg/m2; TM participants had a mean height of 161 cm, weight of 71.5 kg, and BMI of 28 kg/m2. Among TF participants, 38% were living with HIV, and 31% were receiving PrEP. Regarding anthropometric and laboratory changes during follow-up, TF individuals showed significant increases in weight (1.5 kg, p= 0.035) and estradiol (42 pg/mL, p= 0.001), and a decrease in testosterone (78 ng/dL, p= 0.014). TM individuals showed significant increases in weight (2 kg, p= 0.02), testosterone (359 ng/dL, p= 0.03), LDL cholesterol (7.4 mg/dL, p= 0.004), and hematocrit (5.8%, p= 0.02), as well as decreases in estradiol (31 pg/mL, p= 0.002), LH (9.2 uIU/mL, p= 0.02), prolactin (3.8, p= 0.009), and HDL cholesterol (7.3 mg/dL, p= 0.026). No changes were observed in blood pressure, and no thrombotic events occurred. Hyperprolactinemia was observed in 48% of TF and 34% of TM participants, with spontaneous resolution in 83% of cases. Polycythemia occurred only in TM individuals (39%), and 5% required a phlebotomy. No participants reported regret or discontinuation related to gender identity. CONCLUSION: In our population, GAHT was safe, with no treatment discontinuations due to adverse effects. Transmasculine individuals showed greater variation in the measured parameters.