Incidence of Venous Thromboembolism in Transgender Women Receiving Oral Estradiol

Introduction: One of the most serious known adverse effects of feminizing cross-sex hormone therapy (CSHT) is venous thromboembolism (VTE); however, no study has assessed the incidence of VTE from the hormone therapies used in the United States because previous publications on this topic have originated in Europe. CSHT in the United States typically includes estradiol with the antiandrogen spironolactone, whereas in Europe estradiol is prescribed with the progestin cyproterone acetate. Aim: To estimate the incidence of VTE from the standard feminizing CSHTs used in the United States. Methods: A retrospective chart review of transgender women who had been prescribed oral estradiol at a District of Columbia community health center was performed. Main Outcome Measure: The primary outcomes of interest were deep vein thrombosis or pulmonary emboli. Results: From January 1, 2008 through March 31, 2016, 676 transgender women received oral estradiol-based CSHT for a total of 1,286 years of hormone treatment and a mean of 1.9 years of CSHT per patient. Only one individual, or 0.15% of the population, sustained a VTE, for an incidence of 7.8 events per 10,000 person-years. Conclusion: There was a low incidence of VTE in this population of transgender women receiving oral estradiol. Copyright (C) 2016, International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.