Gender-affirming hormone therapy may increase risk of high blood pressure

BOSTON – Transgender people have a higher burden of cardiovascular disease and hypertension than cisgender people. However, while doctors have prescribed gender-affirming hormone therapy to transgender men and women for more than 25 years, little is known about how this treatment may impact rates of hypertension in this patient population or how the effects of hormone therapy on blood pressure may change over time.

In the largest and longest observational study of its kind, physician-researchers from Beth Israel Deaconess Medical Center (BIDMC) found that gender-affirming hormone therapy (GAHT) was associated with blood pressure changes in both transgender men and women. Given the higher burden of heart attack, stroke and other cardiovascular conditions among transgender men and women, these new findings underscore the importance of monitoring blood pressure and other preventive screening measures in transgender patients especially after beginning hormone therapies. The study appears in Hypertension, a journal of the American Heart Association.

“There are many important gaps in clinicians’ knowledge about the effects of hormone therapy for transgender people,” said senior author Michael S. Irwig, MD, Director of Transgender Medicine at BIDMC. “Our study sought to address these gaps by recruiting a racially and ethnically diverse pool of participants to examine the time course and magnitude of the effects of gender-affirming hormones on blood pressure.”

Irwig and colleagues followed 470 patients who began GAHT at two medical centers in the Washington, D.C. between 2007 and 2015. Participants were all at least 17 years old and non-cisgender. Of the 470 patients, 247 were transfeminine and 223 were transmasculine; about 27 percent of patients were non-white. Researchers measured each patient’s blood pressure before beginning GAHT to establish a baseline and continued measurements at subsequent clinical visits for up to 57 months.

Within two to four months of beginning hormone therapy, transgender women saw an average decrease of 4.0 mm Hg in their systolic blood pressure, while transgender men saw an average increase of 2.6 mm Hg. The prevalence of stage 2 hypertension (at least 140/90 mm Hg) dropped from 19 percent to 10 percent in the transfeminine group within two to four months of beginning hormone therapy. The use of testosterone in transgender men could lead to an increased risk for heart attack or stroke if they also have untreated high blood pressure.

In addition, the results indicated that some patients experienced different blood pressure effects compared to the majority of those with the same gender identity. Some transgender women and transgender men saw blood pressure rates trend in the opposite direction of their peers. The study authors highlight this is an area that requires further research, noting individuals taking the same medication may react in different ways.

“Further research is needed to understand how different formulations may affect different people and to find out if there are any disparities among Black or Latinx patients,” said Irwig, who is also Associate Professor of Medicine at Harvard Medical School. “A 2020 Scientific Statement from the American Heart Association indicates that it is paramount to include LGBTQ health in clinical training and licensure requirements for health care professionals so that physicians can better address cardiovascular health disparities in the LGBTQ community.”

Study co-authors are Katherine Banks, M.D. and Mabel Kyinn, M.D. of The George Washington School of Medicine & Health Sciences; Shalem Y. Leemaqz, Ph.D. of Flinders University College of Medicine and Public Health; and Eleanor Sarkodie, M.P.H. and Deborah Goldstein, M.D. of the Whitman-Walker Institute.

All authors report no sources of funding and no potential conflicts of interest.

Editor's note: This release is adapted from a press release issued by the American Heart Association.