Global Coagulation Assays in Transgender Women on Oral and Transdermal Estradiol Therapy

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.

Hemostatic considerations for gender affirming care

Gender dysphoria or gender incongruence is defined as "persons that are not satisfied with their designated gender" [1]. The awareness and evidence-based treatment options available to this population have grown immensely over the last two decades. Protocols now include an Endocrine Society Clinical Practice Guideline [1] as well as the World Professional Association of Transgender Health Standards of Care (WPATH SOC) [2]. Hematologic manifestations, most notably thrombosis, are one of the most recognized adverse reactions to the hormones used for gender-affirming care. Therefore, hematologists are frequently consulted prior to initiation of hormonal therapy to help guide safe treatment. This review will focus on the scientific evidence related to hemostatic considerations for various gender-affirming therapies and serve as a resource to assist in medical decision-making among providers and patients.

Thromboembolic risk with gender-affirming hormone therapy: potential role of global coagulation and fibrinolysis assays

Gender-affirming hormonal therapies are a critical component of the care of transgender individuals. Transgender people are commonly prescribed estrogen or testosterone to promote male-to-female or female-to-male transitions and to preserve gender-specific characteristics long-term. However, some exogenous hormones, especially certain estrogen preparations, are an established risk factor of thrombosis. As the number of individuals seeking gender-based care is rising, there is an urgent need to identify and characterize the mechanisms underlying hormone-associated thrombosis and incorporate this information into clinical algorithms for diagnosis and management. Herein, we discuss historical evidence on the incidence of thrombosis and changes in plasma composition in transgender and cisgender cohorts. We present 3 case studies to demonstrate knowledge gaps in thrombosis risk stratification and prediction tools. We also present data from in vitro coagulation and fibrinolysis assays and discuss how information from these kinds of assays may be used to help guide the clinical management of transgender individuals.

Cardiovascular disease and feminizing gender-affirming hormone therapy: Implications for the provision of safe and lifesaving care

Sex recorded at birth, gender identity, and feminizing gender-affirming hormone therapy (fGAHT) likely contribute to cardiovascular disease (CVD) risk in transgender women. Understanding the interplay of these factors is necessary for the provision of safe, affirming, and lifesaving care. Among transgender women taking fGAHT, data show increases in CVD mortality and rates of myocardial infarction, stroke, and venous thromboembolism compared to reference populations, depending on study design and comparators. However, most studies are observational with a paucity of contextualizing information (e.g., dosing, route of administration, gonadectomy status), which makes it difficult to parse adverse fGAHT effects from confounders and interaction with known CVD risk factors (e.g., obesity, smoking, psychosocial and gender minority stressors). Increased CVD risk in transgender women points toward a need for greater attention to CVD management in this population including cardiology referral when indicated and additional research on the mechanisms and mediators of CVD risk.

Transgender health and the impact of aging and menopause

Gender affirming hormone therapy (GAHT) is used by many transgender people to reduce gender incongruence and improve psychological functioning. As GAHT shares many similarities with menopausal hormone therapy, clinicians supporting people through menopause are ideally placed to manage GAHT. This narrative review provides an overview of transgender health and discusses long-term effects of GAHT to consider when managing transgender individuals across the lifespan. Menopause is less relevant for transgender individuals who take GAHT (often given lifelong) to achieve sex steroid concentrations generally in the range of the affirmed gender. For people using feminizing hormone therapy, there is an elevated risk of venous thromboembolism, myocardial infarction, stroke and osteoporosis relative to cisgender individuals. For trans people using masculinizing hormone therapy, there is an increased risk of polycythemia, probable higher risk of myocardial infarction and pelvic pain which is poorly understood. Proactive mitigation of cardiovascular risk factors is important for all transgender people and optimization of bone health is important for those using feminizing hormones. With a lack of research to guide GAHT in older age, a shared decision-making approach is recommended for the provision of GAHT to achieve individual goals whilst minimizing potential adverse effects.

Risk stratification for pregnancy-associated venous thromboembolism: Potential role for global coagulation assays

Risk assessment for venous thromboembolism in pregnancy and the puerperium is currently limited to stratifying clinical surrogate risk factors without high-quality evidence. While the absolute risk of pregnancy-associated venous thromboembolism is low for the vast majority of women, associated morbidity and mortality remains significant. As guidelines for thromboprophylaxis vary widely, some women may be under- or over-anticoagulated, contributing to poor outcomes. New global coagulation assays provide a holistic view of coagulation and may have the potential to detect hypercoagulability in pregnancy, unlike clinically available coagulation assays. However, there are major technical challenges to overcome before global coagulation assays can be realistically proposed as an adjunct to risk assessment for pregnancy-associated venous thromboembolism. This review summarises the literature and controversies in the prediction and prevention of pregnancy-associated venous thromboembolism and outlines the new tools in haematology that may assist in our future understanding of hypercoagulability in pregnancy.

Clinical features and prevalence of Klinefelter syndrome in transgender individuals: A systematic review

OBJECTIVE

Previous studies have suggested a higher prevalence of Klinefelter syndrome amongst transgender individuals. We undertook a systematic review to determine the prevalence of Klinefelter syndrome amongst transgender individuals presumed male at birth and summarize the clinical features and potential treatment implications for individuals with Klinefelter syndrome commencing gender-affirming hormone therapy.

DESIGN

Using preferred reporting items for systematic review and meta-analysis guidelines, we searched EMBASE, MEDLINE and the Cochrane Central Register of Controlled Trials (CENTRAL) up to 31 December 2021. All studies reporting on the prevalence or clinical features of transgender individuals with Klinefelter syndrome were included. This study is registered with the International Prospective Register of Systematic Reviews, number CRD42021227916.

RESULTS

Our search strategy retrieved 11 cohort studies comprising 1376 transgender individuals. In all, 14 of 1376 (1.02%) individuals were diagnosed with Klinefelter syndrome. Based on the seven studies in which karyotype was undertaken in all individuals, the prevalence is 9/1013 (0.88%; 95% CI, 0.41%-1.68%). Case reports highlight unique treatment considerations in this population, including azoospermia, venous thromboembolism, and monitoring of breast cancer and bone health.

CONCLUSIONS

Compared to the general population, observational studies document a higher prevalence of Klinefelter syndrome amongst transgender individuals, though underdiagnosis in the general population limits conclusions. Routine karyotype in transgender people initiating gender-affirming hormone therapy is not supported unless clinical features of Klinefelter syndrome, such as small testicular volume, or hypergonadotropic hypogonadism are present. Transgender individuals with Klinefelter syndrome need to manage a unique risk profile if they desire feminizing gender-affirming hormone therapy.

Gender-affirming hormone therapy: An updated literature review with an eye on the future

In line with increasing numbers of transgender (trans) and gender nonbinary people requesting hormone treatment, the body of available research is expanding. More clinical research groups are presenting data, and the numbers of participants in these studies are rising. Many previous review papers have focused on all available data, as these were scarce, but a more recent literature review is timely. Hormonal regimens have changed over time, and older data may be less relevant for today's practice. In recent literature, we have found that even though mental health problems are more prevalent in trans people compared to cisgender people, less psychological difficulties occur, and life satisfaction increases with gender-affirming hormone treatment (GAHT) for those who feel this is a necessity. With GAHT, body composition and contours change towards the affirmed sex. Studies in bone health are reassuring, but special attention is needed for adolescent and adult trans women, aiming at adequate dosage of hormonal supplementation and stimulating therapy compliance. Existing epidemiological data suggest that the use of (certain) estrogens in trans women induces an increased risk of myocardial infarction and stroke, the reason that lifestyle management can be an integral part of trans health care. The observed cancer risk in trans people does not exceed the known cancer-risk differences between men and women. Now it is time to integrate the mostly reassuring data, to leave the overly cautious approach behind, to not copy the same research questions repeatedly, and to focus on longer follow-up data with larger cohorts.

Thrombophilia and hormonal therapy in transgender persons: A literature review and case series

Background: Venous thromboembolism (VTE) is a rare side effect of hormonal therapy in transgender persons. Prothrombotic genetic variants can increase this risk. For this reason, previous VTE and/or genetic thrombophilia may be considered by some as contraindications to hormonal treatment. Aim: To formulate directions for clinical practice about the indications for thrombophilia screening and when to consider combination therapy of therapeutic anticoagulation and hormonal treatment as a safe alternative to withholding hormonal treatment. Methods: We conducted a literature search and describe a case series. All adult patients with gender dysphoria and a known prothrombotic genetic variant or history of VTE were invited by letter to participate in this study. Results: In our center, thrombophilia screening before start of hormonal treatment was restricted to those with a personal or family history of VTE. Sixteen individuals with a history of VTE and/or an underlying prothrombogenic condition were described. The time of follow up varied from 4 months to 20 years. Seven trans women had a positive thrombophilia screening (2 Factor V Leiden (FVL), 1 FVL + anticardiolipin antibodies, 1 FVL + high Factor VIII coagulant activity, 1 protein C deficiency, 1 prothrombin mutation, 1 positive lupus anticoagulant). Three trans women experienced an unprovoked VTE after start of hormonal therapy of which one lead to a positive thrombophilia screening. One VTE event in a trans woman was assumed to be provoked by surgery. Five trans men were identified with a prothrombogenic mutation (3 FVL, 1 protein C deficiency, 1 prothrombin mutation). One trans man, with a negative thrombophilia screen, experienced multiple provoked VTE events before start of hormonal therapy. Conclusion: Based on our literature review and case series we offer guidance when confronted with patients with previous VTE and/or genetic thrombophilia requesting hormonal interventions.

Global coagulation assays in hypercoagulable states

Thrombosis is one of the major global causes of morbidity and mortality, and predicting the risk of thrombotic and cardiovascular complications remains one of the key challenges in modern medicine. Conventional coagulation testing does not provide sufficient information, primarily because they measure the time to start of blood clotting and do not evaluate total thrombin generation. Possible adjunctive tools that may be helpful are global coagulation assays, which includes the assessment of the final products of the coagulation cascade, namely thrombin and fibrin. Whilst these assays have been more widely investigated in bleeding states, their role in thrombotic disorders is less established. We have previously investigated the use of assays such as thromboelastography, calibrated automated thrombogram and overall haemostatic potential assay in several hypercoagulable states including cardiovascular disease, haematological disorders and influence of hormone status as well as healthy controls. We provide a review of the use and limitations of global coagulation assays in healthy controls as well as hypercoagulable conditions.

Effect of gender-affirming hormone use on coagulation profiles in transmen and transwomen

BACKGROUND

The transgender population that uses gender-affirming hormone therapy (GAHT) is rapidly growing. The (side) effects of GAHT are largely unknown. We examined the effect of GAHT on coagulation parameters associated with venous thromboembolism (VTE) risk.

METHODS

Factor (F)II, FIX, FXI, protein (p)C and free pS, fibrinogen, hematocrit, sex hormone-binding globulin, and normalized activated protein C ratio were measured in 98 transwomen (male sex at birth, female gender identity) and 100 transmen (female sex at birth, male gender identity) before and after 12 months of GAHT (oral or transdermal estradiol and anti-androgens in transwomen, transdermal or intramuscular testosterone in transmen). Mean paired differences in coagulation measurements were estimated with 95% confidence intervals (95% CI). Differences for route of administration and age were assessed with linear regression.

RESULTS

After GAHT, transwomen had more procoagulant profiles with a mean increase in FIX: 9.6 IU/dL (95% CI 3.1-16.0) and FXI: 13.5 IU/dL (95% CI 9.5-17.5), and a decrease in pC: -7.7 IU/dL (95% CI -10.1 to -5.2). Changes in measures of coagulation were influenced by route of administration (oral vs. transdermal) and age. A higher sex-hormone binding globulin level after 12 months was associated with a lower activated protein C resistance. In transmen, changes were not procoagulant overall and were influenced by age. Differences for route of administration (transdermal vs. intramuscular) were small.

CONCLUSIONS

GAHT in transmen was not associated with apparent procoagulant changes, which provides some reassurance regarding VTE risk. In transwomen, GAHT resulted in procoagulant changes, which likely contributes to the observed increased VTE risk.

Feminizing Hormone Therapy Prescription Patterns and Cardiovascular Risk Factors in Aging Transgender Individuals in Australia

CONTEXT

The safety and efficacy of feminizing hormone therapy in aging transgender (trans) individuals is unclear. Current recommendations suggest transdermal estradiol beyond the age of 45 years, especially if cardiometabolic risk factors are present.

OBJECTIVE

To evaluate feminizing hormone therapy regimens and cardiovascular risk factors in aging trans individuals.

DESIGN

Retrospective cross-sectional analysis.

SETTING

Primary care and endocrine specialist clinic in Melbourne, Australia.

PARTICIPANTS

Trans individuals on feminizing therapy for ≥6 months.

MAIN OUTCOMES MEASURES

Feminizing hormone regimens and serum estradiol concentrations by age group: (a) ≥45 years, (b) <45 years, and prevalence of cardiometabolic risk factors in individuals ≥45 years.

RESULTS

296 individuals were stratified by age group: ≥45 years (n=55) and <45 years (n=241). There was no difference in median estradiol concentration between groups (328 nmol/L vs. 300 nmol/L, p=0.22). However, there was a higher proportion of individuals ≥45 years treated with transdermal estradiol (31% vs. 8%, p<0.00001). Of those treated with oral estradiol, the median dose was lower in the ≥45 years group (4mg vs. 6mg, p=0.01). The most prevalent cardiometabolic risk factor in the ≥45 years group was hypertension (29%), followed by current smoking (24%), obesity (20%), dyslipidaemia (16%) and diabetes (9%).

CONCLUSIONS

A greater proportion of trans individuals ≥45 years of age were treated with transdermal estradiol. Of those who received oral estradiol, the median dose was lower. This is important given the high prevalence of cardiometabolic risk factors in this age group, however cardiovascular risk management guidelines in this demographic are lacking.