Assessing and Addressing the Risk of Venous Thromboembolism Across the Spectrum of Gender Affirming Care: A Review

Abstract

Objective: Accumulating evidence demonstrates that gender affirming hormone therapy (GAHT) improves mental health outcomes in transgender persons. Data specific to the risks associated with GAHT for transgender persons continue to emerge, allowing for improvements in understanding, predicting, and mitigating adverse outcomes while informing discussion about desired effects. Of particular concern is the risk of venous thromboembolism (VTE) in the context of both longitudinal GAHT and the perioperative setting. Combining what is known about the risk of VTE in cisgender individuals on hormone therapy (HT) with the evidence for transgender persons receiving HT allows for an informed approach to assess underlying risk and improve care in the transgender community.

Observations: Hormone formulation, dosing, route, and duration of therapy can impact thromboembolic risk, with transdermal estrogen formulations having the lowest risk. There are no existing risk scores for VTE that consider HT as a possible risk factor. Risk assessment for recurrent VTE and bleeding tendencies using current scores may be helpful when assessing individual risk. Gender affirming surgeries present unique perioperative concerns, and certain procedures include a high likelihood that patients will be on exogenous estrogens at the time of surgery, potentially increasing thromboembolic risk.

Conclusions and relevance: Withholding GAHT due to potential adverse events may cause negative impacts for individual patients. Providers should be knowledgeable about the management of HT in transgender individuals of all ages, as well as in the perioperative setting, to avoid periods in which transgender individuals are off GAHT. Treatment decisions for both anticoagulation and HT should be individualized and tailored to patients' overall goals and desired outcomes, given that the physical and mental health benefits of gender affirming care may outweigh the risk of VTE.

Keywords: clinical risk; gender affirming hormone therapy; transgender; venous thromboembolism.

Figure 1.

Estimated Risk of VTE in Cisgender Women *Pregnancy data based on actual duration of pregnancy in the reference studies. Based on a model assumption that pregnancy duration is nine months, the rate is 7 to 27 per 10,000 PY.