Gender-affirming estrogen therapy route of administration and cardiovascular risk: a systematic review and narrative synthesis

Cross-Sex Hormone Therapy Is Associated With Loss of Circadian Rhythm in the Male Rat

BACKGROUND

Transgender women are individuals born male but identify as female. Many transgender women undergo gender-affirming hormone therapy to alleviate the distress that can occur due to gender incongruence. For transgender women, gender-affirming hormone therapy includes 17β-estradiol (E2) combined with an antiandrogen therapy (AA) or surgical intervention. Numerous studies suggest that the risk of cardiovascular disease is elevated in transgender women; yet, the biological effects of gender-affirming hormone therapy on cardiovascular health are unknown. We hypothesize that a shift in the hormonal milieu versus natal sex in the male rat is associated with an increase in blood pressure at baseline and an enhanced responsiveness to a hypertensive challenge.

METHODS

We developed clinically relevant models that mimic gender-affirming hormone therapy combination therapies utilized for the endocrine treatment of gender dysphoria in transgender women.

RESULTS

Chronic E2 plus castration or the E2+antiandrogen spironolactone was associated with a significant reduction in lean mass and testosterone. At baseline, 24-hour mean arterial pressure did not differ in E2+castration or E2+antiandrogen therapy versus control, but circadian rhythm was disrupted. In response to chronic Ang II (angiotensin II; 200 ng/kg per minute), the Ang II-induced increase in blood pressure was attenuated in E2+castration compared with control, but the blood pressure response to Ang II was similar in E2+antiandrogen therapy versus control.

CONCLUSIONS

Thus, these data indicate that the type of combination therapy utilized may exert differential effects on blood pressure and that disruption of circadian rhythm may be a contributory factor to the increased risk of adverse cardiovascular outcomes in transgender women exposed to high 17β-estradiol coupled to androgen suppression.

Transgender and Nonbinary Individuals' Perceptions Regarding Gender-Affirming Hormone Therapy and Cardiovascular Health: A Qualitative Study

BACKGROUND

Transgender and nonbinary individuals face substantial cardiovascular health uncertainties. The use of gender-affirming hormone therapy can be used to achieve one's gender-affirming goals. As self-rated health is an important predictor of health outcomes, an understanding of how this association is perceived by transgender and nonbinary individuals using gender-affirming hormone therapy is required. The objective of this research was to explore transgender and nonbinary individuals' perceptions of cardiovascular health in the context of using gender-affirming hormone therapy.

METHODS

In this qualitative study, English-speaking transgender and nonbinary adults using gender-affirming hormone therapy for 3 months or more were recruited from across Canada using purposive and snowball sampling methods. Semistructured interviews were conducted through videoconference to explore transgender and nonbinary individuals' perceptions of the association between gender-affirming hormone therapy and cardiovascular health between May and August 2023. Data were transcribed verbatim, and transcripts were analyzed independently by 3 reviewers using thematic analysis.

RESULTS

Twenty-one participants were interviewed (8 transgender women, 9 transgender men, and 3 nonbinary individuals; median [range] age, 27 [20-69] years; 80% White participants). Three main themes were identified: cardiovascular health was not a primary concern in the decision-making process with regard to gender-affirming hormone therapy, the improved well-being associated with gender-affirming hormone therapy was felt to contribute to improved cardiovascular health, and health care provider knowledge and attitude facilitate the transition process.

CONCLUSIONS

Gender-affirming hormone therapy in transgender and nonbinary individuals is perceived to improve cardiovascular health. Given the positive associations between care aligned with patient priorities, self-rated health, and health outcomes, these findings should be considered as part of shared decision-making and person-centered care.

Metabolic and cardiovascular risks of hormone treatment for transgender individuals

Identifying metabolic and cardiovascular risks of gender-affirming hormone therapy (GAHT) is challenging due to other confounding variables that affect patient outcomes and the diversity of treatment regimes. Masculinising hormone therapy produces atherogenic lipid profiles, while effects on other metabolic parameters are not consistent. There is insufficient evidence to conclude if cardiovascular disease risk among transmen is increased. The effects of feminising hormone therapy on metabolic parameters do not demonstrate a consistent pattern in the available literature. However, the risk of venous thromboembolism is greater in transwomen than in cis-gender men and women with a possible increase in cardiovascular disease risk. It is recommended to discuss the potential effects of GAHT on cardiovascular health and encourage patients seeking GAHT to adopt a healthy lifestyle. Performing baseline and periodic assessments of cardiovascular risk factors would enable early identification and interventions. In high-risk individuals, the cardiovascular effects of hormonal regimes might impact the treatment decision.

Association between serum estradiol and cardiovascular health among transgender adults using gender-affirming estrogen therapy

Gender-affirming estrogen therapy (GAET) is commonly used for feminization in transgender and nonbinary (TNB) individuals, yet the optimal rate of change (ROC) in estradiol levels for cardiovascular health is unclear. We examined the association between serum estradiol levels and cardiovascular-related mortality, adverse events, and risk factors in TNB adults using GAET. Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, and Web of Science were systematically searched (inception-April 2023) for original articles reporting serum estradiol levels and cardiovascular-related mortality, adverse events, and risk factors in TNB adults using GAET. Data extraction was completed in duplicate following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Stratified random effect meta-analyses using serum estradiol ROC (serum estradiolbaseline - serum estradiolfollow-up/study duration) was used to assess longitudinal studies (low, 0 < ROC ≤ 1 pg/mL/mo; moderate, 1 < ROC ≤ 3 pg/mL/mo; high, ROC ≥ 3 pg/mL/mo). Thirty-five studies (13 cross-sectional, 19 cohort, and 3 trials) were included. Two studies collectively reported 50 cardiovascular-related deaths, and four collectively reported 23 adverse cardiovascular events. Nineteen studies reporting cardiovascular risk factors were meta-analyzed by ROC stratum (low = 5; moderate = 6; high = 8), demonstrating an association between moderate [0.40, 95% confidence interval (CI): 0.22, 0.59 kg/m2, I2 = 28.2%] and high (0.46, 95% CI: 0.15, 0.78 kg/m2; I2 = 0.0%) serum estradiol ROC and increased body mass index. High (-6.67, 95% CI: -10.65, -2.68 mg/dL; I2 = 0.0%) serum estradiol ROC was associated with decreased low-density lipoproteins. Low (-7.05, 95% CI: -10.40, -3.70 mmHg; I2 = 0.0%) and moderate (-3.69, 95% CI: -4.93, -2.45 mmHg; I2 = 0.0%) serum estradiol ROCs were associated with decreases in systolic blood pressure. In TNB adults using GAET, serum estradiol ROC may influence cardiovascular risk factors, which may have implications for clinical cardiovascular outcomes.NEW & NOTEWORTHY In this systematic review and meta-analysis of 35 studies involving 7,745 participants, high rates of serum estradiol change were associated with small increases in body mass index. Moderate to high rates of change were associated with decreases in low-density lipoprotein. Low rates of change were associated with small decreases in systolic blood pressure. Rate of serum estradiol change in adults using gender-affirming estrogen therapy may influence cardiovascular risk factors, though further research is warranted.

Sex as a biological variable for cardiovascular physiology

There have been ongoing efforts by federal agencies and scientific communities since the early 1990s to incorporate sex and/or gender in all aspects of cardiovascular research. Scientific journals provide a critical function as change agents to influence transformation by encouraging submissions for topic areas, and by setting standards and expectations for articles submitted to the journal. As part of ongoing efforts to advance sex and gender in cardiovascular physiology research, the American Journal of Physiology-Heart and Circulatory Physiology recently launched a call for papers on Considering Sex as a Biological Variable. This call was an overwhelming success, resulting in 78 articles published in this collection. This review summarizes the major themes of the collection, including Sex as a Biological Variable Within: Endothelial Cell and Vascular Physiology, Cardiovascular Immunity and Inflammation, Metabolism and Mitochondrial Energy, Extracellular Matrix Turnover and Fibrosis, Neurohormonal Signaling, and Cardiovascular Clinical and Epidemiology Assessments. Several articles also focused on establishing rigor and reproducibility of key physiological measurements involved in cardiovascular health and disease, as well as recommendations and considerations for study design. Combined, these articles summarize our current understanding of sex and gender influences on cardiovascular physiology and pathophysiology and provide insight into future directions needed to further expand our knowledge.

Toward a Better Understanding of Cardiovascular Risk in the Transgender and Gender-Diverse Community: A Global Call to Action

On World Heart Day 2022, the Mexican Society of Cardiology, the Inter-American Society of Cardiology, and the World Heart Federation collaborated on a public call to action regarding the increased risk of adverse cardiovascular health outcomes in transgender and gender diverse (TGD) individuals. The aim of this article is to unpack the numerous factors that contribute to this, such as the social stigma faced by members of the TGD community, their reduced access to clinical care, and the scarcity of research regarding the unique needs of their community, which makes it difficult for clinicians to provide individualized medical care. Decreasing the incidence of adverse cardiovascular events among TGD individuals requires interventions such as educational reform in the medical community, an increase in inclusive research studies, and broader social initiatives intended to reduce the stigma faced by TGD individuals.

Guidelines on the use of sex and gender in cardiovascular research

In cardiovascular research, sex and gender have not typically been considered in research design and reporting until recently. This has resulted in clinical research findings from which not only all women, but also gender-diverse individuals have been excluded. The resulting dearth of data has led to a lack of sex- and gender-specific clinical guidelines and raises serious questions about evidence-based care. Basic research has also excluded considerations of sex. Including sex and/or gender as research variables not only has the potential to improve the health of society overall now, but it also provides a foundation of knowledge on which to build future advances. The goal of this guidelines article is to provide advice on best practices to include sex and gender considerations in study design, as well as data collection, analysis, and interpretation to optimally establish rigor and reproducibility needed to inform clinical decision-making and improve outcomes. In cardiovascular physiology, incorporating sex and gender is a necessary component when optimally designing and executing research plans. The guidelines serve as the first guidance on how to include sex and gender in cardiovascular research. We provide here a beginning path toward achieving this goal and improve the ability of the research community to interpret results through a sex and gender lens to enable comparison across studies and laboratories, resulting in better health for all.

Importance of survey demographic questions to foster inclusion in medicine and research and reduce health inequities for LGBTQIA2S+ individuals

A clear, inclusive, and accurate approach to the collection of demographic information in clinical research and medical practice is critical to understanding the healthcare needs of the specific population. Inclusive demography constitutes appropriate and accurate characterization of an individual's sexual orientation and gender identity (SOGI) data. Appropriate demography fosters sense of inclusion and belonging for those belonging to medically marginalized communities such as the lesbian, gay, bisexual, transgender, queer, intersex, asexual, and Indigenous Two-Spirit (LGBTQIA2S+) communities and improves health outcomes. Acquiring inclusive demographics in healthcare research is needed for the following critical reasons. First, LGBTQIA2S+ individuals experience undue psychological harm when their identities are not appropriately captured in survey data, promoting further alienation of the LGBTQIA2S+ community in medicine and research. Second, LGBTQIA2S+ populations are disproportionately burdened by several major cardiovascular and cardiovascular-associated diseases, including hypertension and diabetes. Failure to include these populations, and accurately characterize their participation, in research leads to failure to identify associations between identities and disease, resulting in worse health outcomes. Furthermore, this lack of precision in current data for sex, gender, and sexual orientation may lead to inaccurate data for all populations, not just the LGBTQIA2S+ community. Finally, there are currently major political and social threats and attacks on the LGBTQIA2S+ community and, in particular, on transgender and gender-diverse individuals. Proper medical inclusion and advocacy for the LGBTQIA2S+ community by the medical community may help protect the community from further undue harm through creating sense of belonging and reductions in marginalization-related health inequities.

Female sex-specific considerations to improve rigor and reproducibility in cardiovascular research

Cardiovascular disease is the leading cause of death in women. Despite recognition of sex-specific differences in cardiovascular health, females are underrepresented across all aspects of cardiovascular research, playing a key role in reducing rigor and reproducibility in cardiovascular research and contributing to these poorer health outcomes. Therefore, we propose a framework to capture factors associated with the female sex at the preclinical, recruitment, data collection, and data analysis stages. In preclinical cardiovascular research, female experimental models are commonly excluded despite similar variability in findings compared with males. To reduce this sex bias, the inclusion of female models and the incorporation of sex as a biological variable are critical to improve reproducibility and inform clinical research and care. Although funding agencies have mandated the inclusion of women in clinical trials, greater efforts are needed to achieve optimal participation-to-prevalence ratio to increase the generalizability of results to real-world settings. Female participants face more stringent exclusion criteria in research compared with males owing to sex-specific factors. However, their routine exclusion from cardiovascular research is not only unethical but limits generalizability and applicability to clinical practice. Identifying sex assigned at birth, collecting information on female sex-specific and -predominant factors associated with cardiovascular health and risk, and stratifying data by sex, including adverse events, are essential to ensure reproducibility and relevance of findings to target populations. Increasing female representation and the incorporation of female sex-specific cardiovascular risk factors in cardiovascular research will not only lead to enhanced rigor and reproducibility but improved cardiovascular health for all.

Serum oestradiol levels and risk of adverse cardiovascular events associated with gender-affirming oestrogen therapy: a protocol for a systematic review and meta-analysis

INTRODUCTION

The use of gender-affirming oestrogen therapy (GAOT) is an integral part of the gender-affirming transition process for transgender women (assigned male at birth who identify as women) and gender-diverse individuals. However, its use may present significant cardiovascular implications, which may be influenced by systemic oestradiol levels. Therefore, we aim to establish the association between serum oestradiol levels and incidence of adverse cardiovascular events in individuals using GAOT.

METHODS AND ANALYSIS

We will conduct a systematic review addressing the association between serum oestradiol levels and risk of adverse cardiovascular events in individuals using GAOT. Our primary outcome is the incidence of adverse cardiovascular events, our secondary outcome is the incidence of cardiovascular-related mortality and our tertiary outcome is cardiovascular-related risk factors. Electronic databases (Cochrane Central Register of Controlled Trials, Embase, MEDLINE and Web of Science) will be searched from inception until September 2022. Two investigators will independently complete screening to determine appropriateness of inclusion. Extracted data will include information on serum sex hormone levels (oestradiol and testosterone), participants, GAOT (route of administration, formulations, dosages and duration of exposure), incidence of cardiovascular outcomes, study quality and risk of bias. Inter-reviewer reliability will be calculated at both phases. Data will be presented both descriptively and meta-analysed using a random effects model, if appropriate. Heterogeneity will be explored and meta-regressed if noted.

ETHICS AND DISSEMINATION

Ethics approval is not needed. We will disseminate findings through international conferences, distributions to transgender and gender-diverse support organisations, decision-makers and key stakeholders. The final systematic review will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

CRD42021247717.

Hormonothérapies de transition chez les personnes transgenres

Aujourd’hui encore, la prise en charge médicale des personnes transgenres pâtit d’une insuffisance d’offre de soins et de formation des soignants. La mise en œuvre d’une hormonothérapie est souvent souhaitée par les personnes transgenres et il est nécessaire qu’un médecin sache l’instaurer et la suivre tout au long de la transition. Nous abordons dans cette revue le traitement hormonal féminisant (THF) chez les femmes transgenres adultes, et le traitement hormonal masculinisant (THM) chez les hommes transgenres adultes.