Incidence and Factors Associated With Acne Among Transgender Patients Receiving Masculinizing Hormone Therapy.

Importance: Acne is a common condition among transgender patients receiving masculinizing hormone therapy (MHT), but the incident risk and predictors of developing acne in this population have not yet been studied on a large scale. Objective: To assess risk of acne among a large population of transgender patients receiving MHT and clinical risk factors for acne diagnosis. Design, Setting, and Participants: A retrospective cohort study that included 988 patients who started MHT between January 1, 2014, and December 31, 2017, with at least 1 year of follow-up was performed. Data analysis was conducted from September 1 to 15, 2019. Data were obtained using electronic health records from a community health center serving the sexual and gender minority community. The population included every patient who began receiving MHT during the study period who was aged 18 years or older at the time of MHT initiation and whose assigned sex at birth was female. Main Outcomes and Measures: The main outcome was acne defined by International Statistical Classification of Diseases, Tenth Revision, Clinical Modification codes for acne. Overall prevalence and incidence proportions over 2 years after initiation of MHT were calculated. Baseline demographic and clinical characteristics were collected at the time of MHT initiation. A series of univariate analyses for all factors was calculated to test for an association with acne diagnosis, followed by multivariate analyses to test for independent predictors. Results: For 988 patients (median age, 25.8 years; interquartile range, 20.8-28.2 years), there was an overall acne prevalence of 31.1% (n = 307). The 1-year post-MHT acne incidence proportion was 19.0% and the 2-year incidence proportion was 25.1%. A younger age at MHT initiation was associated with a higher likelihood of developing acne, with a median of 22.4 years (interquartile range, 19.7-25.6 years) among patients who developed acne vs 24.7 years (interquartile range, 21.3-29.4 years) among patients who did not (P = .002). Conclusions and Relevance: Acne is a common condition among transgender patients on MHT, with a prevalence increasing from 6.3% to 31.1% following MHT initiation. Patients aged 18 to 21 years appear to be the most likely to develop acne after MHT initiation.