Clinical and Biochemical Outcomes in Transgender Individuals Undergoing Hormone Therapy: Protocol for a Systematic Review.

Background: Monitoring of various clinical outcomes and parameters, such as lipid levels, is recommended in transgender individuals undergoing hormone therapies. However, comprehensive data to inform these recommendations is scarce.

Objective: This study aims to conduct a systematic review and meta-analysis to synthesize evidence from existing literature on the effect of exogenous hormone therapy on clinical and biochemical outcomes for transgender adolescents and adults.

Methods: We will search multiple electronic databases and will include prospective and retrospective observational studies with and without a control group. The study population will include transgender individuals undergoing hormone therapy with testosterone or estrogen. Comparisons will include age-matched, cisgender individuals and changes from baseline. Primary outcomes include changes in or the development of abnormal lipid parameters. Secondary outcomes include BMI, weight, height, and blood pressure for age, serum testosterone or estrogen levels, and development of disease including hypertension, diabetes, fatty liver disease, obesity, adverse cardiac events, as well as all-cause mortality. The meta-analysis will pool the studies where applicable, and meta-regressions will be conducted to evaluate effect modifiers. The GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach will be used to evaluate the overall certainty of evidence.

Results: We will summarize the selection of the eligible studies using a PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flowchart. The results will be presented in a table summarizing the evidence. Data collection is ongoing, and the paper is expected to be published in Spring 2025.

Conclusions: This systematic review will summarize and evaluate the evidence of the clinical and biochemical outcomes associated with hormone therapies for transgender individuals.

Trial registration: PROSPERO CRD42024483138; https://tinyurl.com/yc4sfvnb.

International registered report identifier (irrid): PRR1-10.2196/57931.