Gender-Affirming Hormone Therapy Linked to Blood Pressure Changes in Transgender Individuals

Michael S. Irwig, MD

A new study from physician-researchers at Beth Israel Deaconess Medical Center (BIDMC) is providing insight into the impact of gender-affirming hormone therapy on blood pressure in transgender individuals.

The largest and longest study of its kind to date, results indicate gender-affirming hormone therapy (GAHT) was associated with blood pressure decreases among transfeminine patients but increases among transmasculine patients.

"There are many important gaps in clinicians' knowledge about the effects of hormone therapy for transgender people," said senior investigator Michael Irwig, MD, Director of Transgender Medicine at BIDMC, in a statement. "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."

With an interest in further understanding the potential impact of GAHT on cardiovascular risk in transgender men and women, Irwig and colleagues designed their study as a chart review to assess changes in blood pressure among patients who initiated GAHT at a pair of Washington, DC-based medical centers. Using information from the Medical Faculty Associates of The George Washington University and Whitman-Walker Health, investigators identified 470 transgender and gender-diverse adult patients for inclusion. This cohort included 247 transfeminine and 223 trans masculine patients with a mean age of 27.8 years. Investigators pointed out this cohort was made up of patients with ethnically diverse backgrounds, with non-Hispanic White patients making up less than 75% of the population.

Inclusion criteria included being 17 years of age or older, a noncisgender identity, and having data related to follow-up visits for at least 3 months for Medical Faculty Associates patients and at least 2 years for Whitman-Walker Health Patients. Investigators also noted patients were required to have baseline visits occurring between January 1, 2007 and June 1, 2015.

Among transfeminine patients, 92% were initially started on 17β-estradiol and the mean dose generally increased over time and the second most common regimen was intramuscular estradiol valerate or cypionate. Among transmasculine patients, between 77-91% were on intramuscular testosterone esters and the remainder were on transdermal formulations. Of note, a history of previous GAHT 6 months or more before the baseline visit was reported by 15% of transfeminine and 5% of trans masculine individuals.

For the purpose of analysis, blood pressure was measured at baseline and at multiple follow-up clinical visits up to 57 months after the initiation of GAHT. The outcomes of interest for the investigators’ analyses were changes to SBP and DBP following initiation of GAHT and the percentage of patients with elevated SBP (120–129 mmHg), stage 1 hypertension (SBP 130–139 mmHg or DBP 80–89 mmHg), or stage 2 hypertension (SBP at or above 140 mmHg or DBP at or above 90 mmHg) according to the 2017 American College of Cardiology and American Heart Association criteria.

Investigators found within 2-4 months of starting GAHT, mean systolic blood pressure was decreased by a mean of 4.0 mmHg in the transfeminine group (P<.0001) and increased by a mean of 2.6 mmHg in the transmasculine group (P=.02). Further analysis indicated these changes in blood pressure were maintained throughout the duration of the follow-up period. No changes in diastolic blood pressure were observed in either group.

When assessing prevalence of hypertension, investigators found the prevalence of stage 2 hypertension among transfeminine individuals decreased by 47% from 19% of individuals to 10% within 2-4 months of beginning GAHT (P=.001).

In the aforementioned statement, Irwig noted the need for further research into how race/ethnicity might play a role in modifying the risk of changes in blood pressure among transgender patients undergoing GAHT.

“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,” noted Irwig.

This study, “Blood Pressure Effects of Gender-Affirming Hormone Therapy in Transgender and Gender-Diverse Adults,” was published in Hypertension.