Changes in Blood Lipids Following Initiation of Gender Affirming Hormone Therapy: A Systematic Review and Meta-Analysis.

ABSTRACT

Aim: The aim of this study was to conduct a systematic review and meta-analysis of changes in low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), total cholesterol, and triglycerides following initiation of feminizing or masculinizing gender affirming hormone therapy (GAHT). Methods: A search of Ovid MEDLINE, Embase, Web of Science, SCOPUS, and CINAHL databases identified potentially relevant articles published from 1990 through 2024. Both observational and randomized trials of adults receiving feminizing or masculinizing GAHT with baseline and follow-up measures were included. Articles were reviewed for eligibility using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) 2020 guidelines. The risk of bias in each study was quantified using the NHLBI Study Quality Assessment Tool for Before-After (Pre-Post) Studies with No Control Group. Random effects models were used to compute the before-and-after meta-differences in mean values for each parameter along with the I2 statistic to assess heterogeneity of results. Results: Thirty-five studies met the criteria for inclusion in the meta-analysis. Masculinizing GAHT was associated with significant changes in serum lipids from baseline up through the 60-month timepoint with meta-difference of means (95% CI) estimates of 26.2mg/dL (23.3,29.0) for LDL-C, 26.1mg/dL (22.8,29.4) for total cholesterol, 30.7mg/dL (6.9,54.6) for triglycerides and -9.4mg/dL (-12.1, -6.7) for HDL-C. Studies evaluating the effects of feminizing GAHT on balance demonstrated no notable changes in HDL-C or triglycerides while the results for LDL-C and total cholesterol were inconsistent. Heterogeneity of results ranged from minimal (I2 = 0%) to substantial (I2 = 90%). Conclusions: While the results for transfeminine individuals on GAHT appear somewhat reassuring, transmasculine patients receiving testosterone may benefit from closer monitoring of lipid profiles.