OC 38.5 - Venous thromboembolism in Transgender and Gender Diverse Youth is rare and occurs in the setting of additional risk factors.

Background: Transgender and gender diverse (TGD) youth compose approximately 2-3% of United States (US) high school students, and often receive gender-affirming hormone therapy (GAHT). An increased risk of venous thromboembolism (VTE) has been reported in adult transgender females but not transgender men receiving GAHT. Pediatric data are lacking.

Aims: The principal objective of this investigation was to identify the VTE rate and risk profile in TGD youth followed at our quaternary-care center.

Methods: Permission from the Institutional Review Board was obtained. Hospital systems were queried to identify patients followed by the Gender Multispecialty Service, who were diagnosed with gender dysphoria and VTE between 2007-2020. Demographic data were abstracted from patient medical records. Standard statistical methods were used to summarize data. Fisher’s exact test was used to investigate VTE risk with GAHT.

Results: 1860 patients met eligibility criteria for this investigation. 914 (49.4%) had received GAHT, while 986 (50.6%) had not. Mean age at initiation of GAHT was 15.6 years. Five thrombotic events have been documented in 3 (0.2%) patients (table 1). Median age at VTE diagnosis was 15 years. All thrombotic events occurred in the setting of additional risk factors. GAHT was not associated with an increased VTE risk (p-value=1). Two patients developed VTE in the setting of GAHT, both received a short course of anticoagulation and were safely able to resume GAHT. Nine patients with no personal history of VTE were diagnosed with a primary thrombophilia [Factor V Leiden mutation (n=6); prothrombin gene mutation (n=2) and protein S deficiency (n=2)], two of whom received prophylactic anticoagulation during GAHT (table 2).

Conclusion(s): This investigation represents the largest pediatric TGD cohort in the US that has been investigated for VTE. Our data suggest that VTE is rare in this cohort, and GAHT is not associated with an increased risk of VTE.