Kidney Health and Gender-Affirming Hormone Therapy for Transgender and Gender Diverse Individuals

This review examines the effects of gender-affirming hormone therapy (GAHT) on kidney health in transgender and gender diverse (TGD) populations, which face significant challenges in accessing medical care. GAHT typically involves estrogen therapy for transgender women and transfeminine individuals, testosterone therapy for transgender men and transmasculine individuals, and therapy regimens for individuals who are nonbinary or identify with another gender not culturally assigned to their sex assigned at birth. Hormone therapy influences biomarkers such as creatinine and cystatin C, which are used in eGFR. Current eGFR equations, reliant on sex-specific factors, may misrepresent kidney function in TGD individuals, leading to misdiagnosis or misclassification of kidney disease stages. GAHT alters serum creatinine (SCr) and cystatin C differently in individuals who use masculinizing or feminizing hormones. Testosterone therapy often raises SCr, while estrogen therapy may lower or has no effect on SCr levels. In addition, GAHT can affect CKD progression and the incidence of AKI due to a myriad of factors including hormonal effects. Estrogen may offer renal protection, while testosterone may elevate risks. Clearly, more data are needed, especially concerning the long-term effects of GAHT on CKD and AKI incidence and progression among TGD individuals. Kidney transplant considerations for TGD patients are complex, involving factors such as the effect of hormone therapy on allograft and patient survivals, drug-drug interactions, and unique anatomical challenges The lack of inclusive data in kidney disease registries and national databases for TGD populations limits the understanding of the effect of GAHT on kidney health. This narrative review calls for comprehensive and longitudinal research to better define eGFR estimation in TGD individuals using GAHT and the broader implications of GAHT on kidney health outcomes.