Endocrine Abstracts

Background: Transgender people often use gender-affirming hormone therapy to obtain physical characteristics that comply with their experienced gender. Transgender women use estradiol, usually with anti-androgens. Transgender men use testosterone. It has been reported that gender-affirming hormone therapy is associated with increased risk of acute cardiovascular events, however, this data constitutes largely of low quality evidence. We aimed to investigate the long-term incidence of acute cardiovascular events (CVEs) in our large cohort of transgender people compared with incidence in cisgender men and women.

Methods: This retrospective cohort study includes all people who visited the gender identity clinic of the Amsterdam University Medical Centre in the Netherlands between 1972 and 2018. All people were linked to a nationwide data registry (Statistics Netherlands) to obtain data on medical diagnoses, which were registered from 2012 until 2021. The outcomes were myocardial infarction, stroke, thrombosis and overall acute CVE incidence. Exclusion criteria were not using hormones and death before 2012. Standardized incidence ratios (SIRs) for each outcome were calculated using general population incidence rates stratified by age, sex and calendar year.

Results: 2983 transgender women (follow-up: 49440 person-years) and 2143 transgender men (follow-up: 25346 person-years) were included. Median age at hormone therapy initiation was 29 (IQR 22-40) and 21 (IQR 18-28) years, respectively. Transgender women experienced 142 acute CVEs, which was higher compared with cisgender women (SIR 1.5, 95%CI 1.3-1.8), but not cisgender men (SIR 1.1, 95%CI 0.9-1.3). Myocardial infarction incidence was higher compared with cisgender women (SIR 1.8, 95%CI 1.2-2.5), and lower compared with cisgender men (SIR 0.7, 95%CI 0.5-0.9). Thrombosis incidence was elevated compared with both cisgender groups (women: SIR 1.9 [95%CI 1.4-2.4], men: SIR 1.8 [95%CI 1.4-2.4]). Stroke SIR was 1.2 (95%CI 0.9-1.5) compared with cisgender women and 0.9 (95%CI 0.7-1.2) compared with cisgender men. Transgender men experienced 62 CVEs, which was higher compared with cisgender women (SIR 1.9, 95%CI 1.5-2.4) and men (SIR 1.5, 95%CI 1.1-1.9). Myocardial infarction SIRs were also higher than in cisgender women (4.8, 95%CI 3.1-6.9) and men (1.7, 95%CI 1.1-2.4). This was not the case for stroke SIRs (cisgender women: 1.5 [95%CI 0.9-2.1], men: 1.2 [95%CI 0.8-1.8]) and thrombosis SIRs (cisgender women: 1.2 [95%CI 0.7-1.9], men: 1.5 [95%CI 0.9-2.4]).

Conclusion: Transgender women have a higher overall CVE risk than cisgender women, particularly in thrombosis and myocardial infarction. For transgender men overall CVE risk is higher than in both cisgender groups, mostly affected by increased myocardial infarction risk.