Estrogen Use and the Risk for Blood Clots and Strokes Among Transgender Women
A PCORI-funded study provides new information for primary care clinicians about the need to monitor long-term cardiovascular risks in transgender women receiving hormone therapy.1
Approximately 1.4 million transgender people live in the United States.2 Many transgender women pursue medical transition with hormone therapy including estrogen to align their bodies with their female gender identity. Evidence suggests that medical transition confers significant psychological benefits including reduced depression, anxiety, and suicidality3 and improved quality of life.4 However, the risks of using estrogen, including cardiovascular risks, are not well understood. Recent evidence on these risks can help inform decisions and improve care for transgender women who are currently using or formerly used estrogen.
FindingsA PCORI-funded research study1 found that incidences of venous thromboembolism (VTE) and ischemic stroke (IS) were higher in transgender women receiving estrogen than in cisgender men and women. The difference in risk increased over time. After eight years, the study found 17 excess cases of VTE per 1,000 transgender women compared with cisgender men and 14 excess cases of VTE per 1,000 transgender women compared with cisgender women. Transgender women had higher rates of myocardial infarction than cisgender women; these rates were similar to those observed in cisgender men.
This study suggests that clinicians caring for transgender women receiving estrogen as part of medical transition should be alert to potential long-term vascular side effects of estrogen therapy.
Approximately 60 percent of both the transgender and cisgender cohorts in this study were ages 18 to 45 years. Cardiovascular risks, which increase with age, may be higher for older transgender women receiving estrogen therapy. This risk should be appropriately considered in relation to the benefits of treatment and monitored as a part of ongoing medical care.4
Evidence-Based Care for Transgender Patients
Evidence-based practices for the medical care of transgender patients using hormone therapy include:5,6
➤ Assessing additional risk factors for clotting or strokes, such as body mass index and tobacco use
➤ Providing ongoing medical monitoring of the effects and side effects of estrogen use, which includes appropriate signs of feminization and the development of adverse reactions
Communicating with Patients about Hormone Therapy
A patient version of this evidence update is available here. The patient version is designed to help transgender women in their discussions with clinicians, highlighting the importance of long-term monitoring for VTE and IS. Topics clinicians may wish to discuss with patients include the following:
➤ A research study found that transgender women who took estrogen were at higher risk for blood clots and stroke than cisgender women and men not receiving hormones.
➤ Patients should weigh the potential cardiovascular risks of estrogen therapy against the psychological benefits.
➤ Risks for blood clots and strokes may be lessened through healthy habits such as exercising, eating more fruits and vegetables, and quitting smoking.7
➤ Symptoms of blood clots include swelling in an arm or leg, pain or tenderness, discoloration and abnormal warmth, chest pain and heavy breathing, shortness of breath, sudden cough, and chronic headaches.
➤ Symptoms of stroke include face drooping, arm weakness, and slurred speech.8,9
➤ Transgender women should develop a schedule with their clinician for long-term monitoring of cardiovascular health, even after stopping estrogen.
About the StudyA team of researchers compared up to 10 years of medical records for 2,842 transgender women and 2,118 transgender men who were matched with 48,686 cisgender men and 48,775 cisgender women to understand how hormone use affects the risk for VTE, IS, and myocardial infarction. The study also examined testosterone use for transgender men but did not find sufficient evidence to draw conclusions about increased risks of acute cardiovascular events.
Read more about this study at: www.pcori.org/Goodman076
PCORI produced this Evidence Update in collaboration with the National LGBT Health Education Center (a program of the Fenway Institute), WPATH: World Professional Association for Transgender Health, and Nurse Practitioners in Women's Health
1. Getahun D, Nash R, Flanders WD, et al. Cross-sex hormones and acute cardiovascular events in transgender persons: A cohort study. Ann Intern Med. 2018;169(4):205-213.
2. Flores AR, Herman JL, Gates GJ, et al. How Many Adults Identify as Transgender in the United States? Los Angeles, CA: The Williams Institute; 2016.
3. Owen-Smith AA, Gerth J, Sineath RC, et al. Association between gender confirmation treatments and perceived gender congruence, body image satisfaction, and mental health in a cohort of transgender individuals. J Sex Med. 2018;15(4):591-600.
4. Rowniak S, Bolt L, Sharifi C. The effect of cross-sex hormones on the quality of life, depression and anxiety of transgender individuals: A quantitative systematic review. JBI Database of Systematic Reviews and Implementation Reports. 2019;17(9):1826-1854.
5. Coleman E, Bockting W, Botzer M, et al. Standards of Care for the Health of Transsexual, Transgender, and Gender-Nonconforming People. 7th ed. Minneapolis, MN: World Professional Association for Transgender Health; 2012. https://wpath.org/media/cms/Documents/SOC%20v7/Standards%20of%20Care_V7%20Full%20Book_English.pdf. Accessed January 16, 2020.
6. Deutsch MB, ed. Guidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People. 2nd ed. San Francisco: UCSF Transgender Care, Department of Family and Community Medicine, University of California San Francisco; 2016. http://www.transhealth.ucsf.edu/trans?page=guidelines-home. Accessed January 16, 2020.
7. American Heart Association. Healthy Living. https://www.heart.org/en/healthy-living. Accessed January 16, 2020.
8. National Blood Clot Alliance. Stop The Clot. https://www.stoptheclot.org/learn_more/signs-and-symptoms-of-blood-clots/. Accessed January 16, 2020.
9. American Stroke Association. Stroke Symptoms. https://www.strokeassociation.org/en/about-stroke/stroke-symptoms. Accessed January 16, 2020.
The information in this publication is not intended to be a substitute for professional medical advice. This update summarizes findings from a PCORI research award to Emory University.
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