Incidence, Contributing Factors, and Implications for Clinical Management of Polycythemia in Transmasculine Patients on Testosterone.

Purpose: The goal of this study was to evaluate contributing factors and management strategies for polycythemia in transmasculine patients on testosterone therapy. Methods: A retrospective analysis of medical records was performed for transmasculine patients on testosterone for at least 12 months. Data collected from each patient included age, body mass index (BMI), nicotine dependence, pulmonary disease status, obstructive sleep apnea (OSA) status, oophorectomy status, and testosterone route of administration. For patients who developed polycythemia, polycythemia management strategy data were collected. Results: Five-hundred-eleven patients were evaluated and 113 (22%) experienced an episode of polycythemia. Within the polycythemia group, 77% of patients were younger than age 40, 56% had a BMI >30.0, 44% had current or former nicotine dependence, 12% had a pulmonary disease, 12% had OSA, and 47% had received an oophorectomy. The polycythemia group had a significantly higher average age, BMI, and dose of testosterone, and also had a higher proportion of patients with OSA and an oophorectomy. Conclusion: These results revealed that polycythemia is a common side effect for transmasculine patients on testosterone. Importantly, previous oophorectomy may be associated with polycythemia which appears to be a novel finding. This finding requires further research but provides the potential to be an important screening consideration for transmasculine patients after oophorectomy. Polycythemia will continue to be a major concern for patients on testosterone therapy, and this study provided important information for clinical practice and future research that will lead to improved outcomes.