# Thrombosis Risk in Transgender Adolescents and Young Adults Starting Gender-Affirming Hormone Therapy

> **NIH NIH R01** · CINCINNATI CHILDRENS HOSP MED CTR · 2022 · $450,554

## Abstract

PROJECT SUMMARY
Gender-affirming hormone therapy (GAHT) is one of the most effective interventions for treating gender dys-
phoria in transgender and gender nonconforming (hereafter transgender) youth, thereby reducing suicide risk.
GAHT, particularly estrogen, may increase the risk of thrombosis. While hematologists often evaluate patients
before GAHT start who are at risk of thrombosis due to personal/family risk factors, there are no guidelines or
data to inform management. This lack of data leads to significant variation in clinical practice that may com-
promise care. Because this knowledge gap hinders the ability of gender care clinicians and hematologists to
provide optimal care to transgender youth, the objectives of this proposal are to prospectively examine biologic
changes associated with thrombotic risk in a cohort of transgender youth receiving estrogen GAHT and to ex-
amine the attitudes and practices of clinicians who make decisions about thromboprophylaxis for youth on
GAHT. The proposed work is relevant to the priorities of understanding human biology (defining changes in
thrombotic risk associated with estrogen GAHT) and reducing human disease (defining which transgender
youth may benefit from thromboprophylaxis). The proposed research is innovative in the focus on transgender
youth, comprehensive examination of changes in coagulation factors in youth using estrogen GAHT, and de-
termination of factors influencing the treatment recommendations of hematologists for thromboprophylaxis
among transgender youth with personal/family risk factors for thrombosis. The specific aims are to: 1) prospec-
tively determine changes in coagulation that would predispose to thrombosis over the first 24 months of estro-
gen GAHT in a population of transgender women (up to age 22 years at GAHT start); and 2) characterize the
attitudes, practices, and intentions of hematologists caring for youth toward recommending thromboprophylaxis
to TG youth with personal/family risk factors for thrombosis. In Aim 1, 75 transgender women up to 22 years of
age who are starting estrogen GAHT will undergo thorough and systematic evaluation of hemostatic factors at
baseline prior to GAHT start, and then at 3, 6, 12, 18, and 24 months, with interim telephone study visits. Hor-
mone usage and adherence, coagulation parameters, thrombophilia polymorphisms, and platelet activation will
be assessed. In Aim 2, well-established qualitative and survey research methods will be used. Up to 20 adult
and pediatric hematologists will complete individual interviews. Data from these interviews will be used to gen-
erate items for a new survey that will undergo survey development methods (cognitive interviews, pilot testing)
before being fielded to a sample of U.S. and Canadian hematologists to understand their attitudes, behaviors,
and intentions to recommend thromboprophylaxis to transgender youth at risk for thrombosis and factors asso-
ciated with these intentions. The results ...

## Key facts

- **NIH application ID:** 10521357
- **Project number:** 1R01HL161153-01A1
- **Recipient organization:** CINCINNATI CHILDRENS HOSP MED CTR
- **Principal Investigator:** Tanya L. Kowalczyk Mullins
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $450,554
- **Award type:** 1
- **Project period:** 2022-08-01 → 2027-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10521357

## Citation

> US National Institutes of Health, RePORTER application 10521357, Thrombosis Risk in Transgender Adolescents and Young Adults Starting Gender-Affirming Hormone Therapy (1R01HL161153-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10521357. Licensed CC0.

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