Transgender adults, gender-affirming hormone therapy and blood pressure: a systematic review

Objectives: Gender-affirming hormone therapy (GHT) is utilized by people who are transgender to align their secondary sex characteristics with their gender identity. Data relating to cardiovascular outcomes in this population are limited. We aimed to review the impact of GHT on the blood pressure (BP) of transgender individuals. Methods: We searched PubMed/MEDLINE, SCOPUS and Cochrane Library databases for articles published relating to the BP of transgender adults commencing GHT. Methodological quality was assessed via the 'Quality Assessment Tool for Before- After (Pre- Post) Studies with No Control Group'. Results: Six hundred articles were screened, of which 14 studies were included in this systematic review encompassing 1309 individuals (similar to 50% transgender men and women) treated with GHT between 1989 and 2019. These articles were all pre-post observational studies without control groups. Mean ages ranged between 23.0-36.7 years (transgender men) and 25.2-34.8 years (transgender women). Interventions were diverse and included oral, transdermal and injectable hormonal preparations with 4 months to 5 years follow-up. Most studies in transgender men did not demonstrate a change in BP, whereas transgender women on GHT demonstrated both increases and decreases in SBP. These studies were heterogenous with significant methodological limitations and only two were determined to have a good quality rating. Conclusion: There is currently insufficient data to advise the impact of GHT on BP in transgender individuals. Better quality research is essential to elucidate whether exogenous sex hormones modulate BP in transgender people and whether this putative alteration infers poorer cardiovascular outcomes.