Endocrine Abstracts

Background: Testosterone therapy (TTh) may produce various side effects, particularly erythrocytosis, with short-acting testosterone (T) injections presenting the greatest risk. Other causes are smoking and obesity. Erythrocytosis increases blood viscosity, which may lead to thromboembolic complications. Aim: to study the frequency of erythrocytosis induced by TTh and its predictive factors on transgender males (TM) in the Gender Unit of our hospital.

Methods: A retrospective study on TM on TTh for ≥ 3 months was conducted. Age, age at treatment initiation (ATI), months on treatment, anthropometric measures, hematocrit and hormonal levels at last visit, and the highest value of hematocrit (MaxHt) measured were recorded. Additionally, T formulation, smoking status, and previous hysterectomy and mastectomy procedures were also documented. Hematocrit ≥ 50% was considered erythrocytosis and ≥ 53% was indication for phlebotomy.

Results and conclusions: 140 TM were included (M±EEM, min-max): age (29.29±0.82, 15–62 years); ATI (24.06±0.70, 14–54 years); months on treatment (63.07±4.11, 4–276); weight (70.27±1.28, 40–117 kg); height (162.10±0.48, 146–179 cm); BMI (26.72±0.49, 14.9–49 kg/m²); waist perimeter (85.45±1.12, 59–121.5 cm); hip perimeter (98.53±0.87, 74.5–136 cm); waist-hip ratio (0.87±0.01, 0.72–1.13); body fat % (29.40±0.71, 9–49); hematocrit (46.93±0.34, 37.0–59.3%); MaxHt (48.44±0.32, 26.7–55.1%); total T (5.13±0.35, 0.2–22.7 ng/ml); SHBG (23.89±1.44, 5.3–139.6 nmol/l); estradiol (38.34±1.50, 20–107 pmol/ml); FSH (19.33±2.96, 0.1–214 mUI/ml); LH (9.84±1.41, 0.1–73.7 mUI/ml) and PRL (12.30±0.83, 2.83–83.2 ng/ml) levels. The number of smokers, those undergone hysterectomy and mastectomy were 51, 76 and 80 respectively. There were 9 TM on transdermal T gels, 100 on short-acting IM T injections and 31 on extended-release IM T injections. Hematocrit and MaxHt were ≥ 50% in 31 and 46 (30%) persons, and ≥ 53% in 5 and 14 (10%) persons respectively. Hematocrit (47.73±0.45 vs 45.96±0.50%, P=0.01) and MaxHt levels (49.69±0.35 vs 46. 96±0.52%, P=0.0001) were higher in hysterectomized persons, while in smokers only MaxHt was higher (49.03±0.42 vs 48.10±0.45%, P=0.006). On the other hand, nor hematocrit nor MaxHt were related to T formulation, mastectomy or BMI. Moreover, there was no difference in the hormones levels between the three T preparations. In conclusion, erythrocytosis frequency was high (33%), and 10% of treated TM required phlebotomy. Hematocrit values were independent of BMI and type of T preparation, possibly due to the small number of individuals in two of the three treatment groups.