PURPOSE: Surgical treatment of gender dysphoria is a rapidly growing area of interest in Plastic Surgery. Cross-sex hormone treatment is an established component of management and is required by World Professional Association for Transgender Health guidelines prior to surgical interventions. The impact of hormone replacement therapy in gender congruent individuals on hemostatic outcomes is well-established. Unfortunately, comprehensive understanding of its effects on venous thromboembolism (VTE) risk in the transgender population is lacking.
METHODS: A systematic review of the Pubmed, Google Scholar, and EBSCO databases was performed in October 2018. Studies assessing thromboembolic events in transgender patients undergoing cross-sex hormone treatment were included. Review articles, case reports, and studies lacking descriptions of hormone therapies were excluded. Data regarding demographics, hormone therapy, and venous thromboembolism incidence were collected and pooled for analysis. Statistical analysis was performed using a Student’s t-test.
RESULTS: Of 2,948 initial titles, 51 articles were read in their entirety, and 23 were included for pooled analysis. All studies were retrospective in nature. In total, 9,180 transgender patients (6,068 male-to-female and 3,112 female-to-male) underwent cross-sex hormone therapy. Hormone therapies in male-to-female (MTF) patients most commonly consisted of oral or transdermal estrogen formulations with-or-without progestogens. The majority of female-to-male (FTM) patients received intramuscular or oral testosterone. Weighted VTE rates of 2.5% in male-to-female patients (50.6 per 10,000 person-years) and 0.87% (20.7 per 10,000 person-years) in female-to-male patients were observed. When compared to previously published rates in cis-gender patients undergoing hormone replacement therapy, MTF patients did not have a significantly risk for VTE (p=0.953) while FTM patients had significantly lower risk for VTE (p >0.001). Additionally, the data demonstrated a trend towards higher VTE risk in male-to-female patients undergoing oral estrogen treatment compared to transdermal estrogen.
CONCLUSIONS: Hormone therapy in transgender patients is essential to promote a physiologic state aligned with gender identity. However its potential effects on thrombotic complications must be assessed prior to surgical interventions. Transgender patients may undergo invasive surgeries requiring periods of immobilization in order to complete their transitions. Our analysis suggests that MTF patients undergoing cross-sex hormone therapy are at similar risk for VTE to cis-gender individuals undergoing hormone replacement therapy, and FTM patients may have lower risk. Surgical planning regarding perioperative and postoperative VTE prophylaxis or cessation of hormone therapy should take into account each patient’s Caprini risk assessment and the nature of each intervention.