OR05-4 Case Series of Transmasculine Adolescents Who Developed Polycythemia on Gender Affirming Hormone Therapy

STUDY OBJECTIVE: This case series was designed to describe cases of polycythemia among transgender male adolescent patients undergoing treatment with testosterone. METHODS: Retrospective data was collected for our Pediatric Gender Clinic between Jan 2014 and June 2021. Variables assessed included demographic and laboratory data, presence of comorbidities, testosterone dose and level at the time of polycythemia, concurrent treatment with other hormonal treatments, and duration of therapy. Polycythemia in children was defined as hematocrit (HCT) +2 SD above mean for age and gender. Male reference range was used for HCT after 3 months of treatment. RESULTS: Seven of 131 patients were identified with polycythemia (5.3%). The mean age was 17.9 ± 3.7 (SD) years at the time of polycythemia and 6 of 7 patients were overweight or obese. All patients were receiving testosterone by injection. The mean testosterone dose was 51.4 ± 13.3 (SD) mg/m(2)/2wks or 92.9 mg/2wk ±22.1 (SD). All patients developed polycythemia developed at doses below 75 mg/m(2)/2wks. The mean testosterone level at the time of polycythemia was 588 ± 315.3. (SD) ng/dL and the mean length of treatment before polycythemia occurred was 18.6 ± 6.2 (SD) months; the shortest duration of treatment was 10 months. Two patients have received concurrent treatment with progestin therapy. Obstructive sleep apnea (OSA) was identified in 1 patient. CONCLUSION: Polycythemia occurred in 5.3% of our transgender male patients receiving testosterone therapy. This is a known complication of testosterone therapy that may appear with a relatively low dose and after a relatively short duration of treatment. Patient 1Patient 2Patient 3Patient 4*Patient 5Patient 6Patient 7Age at time of polycythemia, years19.116.616.721.816.917.616.6BMI at time of polycythemia, kg/m(2)25.239.634.130.949.619.426.7Smoking/vaping NNNVapingNNNComorbidities: Asthma, OSANAsthma, mild OSAAsthmaNNNNAdditional hormonal therapyNMedroxyprogesterone acetate injectionEtonogestrel implantNNNNHCT level at baseline, %46.544.143.050.444.245.841.1HCT level at the time of polycythemia, % 55.050.150.053.050.550.650.8Testosterone level at the time of polycythemia, ng/dL3997033455254821253416Length of Tx with testosterone, months10141426182523Dose of testosterone, mg/2wk801008060130100100Dose of testosterone, mg/m(2)/2wk47.369.741.231.249.664.556.5Table 1. Characteristics of patients with polycythemia.* Patient was taking an injectable dose of testosterone for 6-8 months prior to the first visit to our clinic Presentation: Saturday, June 11, 2022 12:15 p.m. - 12:30 p.m.