by Carolyn Chu, MD, MSc, AAHIVS, AAHIVM Chief Medical Officer

March 15, 2022

Featured Literature:
Patel N, Blumenthal J, Dubé MP, et al.  Method of calculating renal function estimates could inappropriately exclude transgender patients receiving gender-affirming hormone therapy from pre-exposure prophylaxis eligibility.  LGBT Health.  2022 Feb 23.  doi: 10.1089/lgbt.2021.0219.  Online ahead of print. 

Study investigators quantified the variability in kidney function estimates between three commonly used equations when applied to a population of 258 transgender participants enrolled in a PrEP demonstration project (parent study: ImPrEPT, NCT03086200).  Primary outcome was estimated renal function based on the Cockcroft-Gault, Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations.  Two iterations of calculations were performed, the first using sex assigned at birth and the second gender identity.  Authors observed a median difference of +16 (-11 to +21) mL/min in estimated CLCR when using sex assigned at birth for the gender coefficient vs. gender identity.  Median differences in eGFR when using sex assigned at birth vs. gender identity were +25 (-19 to +33) mL/min and +13 (-10 to +22) mL/min, respectively, for GFRMDRD and GFRCKD-EPI.  Among male sex assigned at birth individuals, significantly higher median renal function estimates were observed among users of gender-affirming therapy than nonusers (this observation was consistent regardless of method or equation used).  Conversely, renal function estimates were lower for female sex assigned at birth users of gender-affirming therapy compared with nonusers.  Overall, 6.6% of participants would have been potentially rendered ineligible for TDF/FTC-based PrEP based on at least one of the equations/methods yielding a creatinine clearance value < 60 mL/min (the proportion varied by equation and gender coefficient used).

Author’s Commentary:

Findings of this study suggest large variability in estimated renal function depending on gender coefficient selection as well as exogenous use of gender-affirming therapy.  Such variability may have clinically meaningful implications at the individual patient level (for both PrEP initiation as well as continuation) but also broader public health impact, given disproportionate rates of HIV in some transgender communities.  Ongoing research is needed to increase understanding of appropriate biomarker and calculation/equation use to accurately assess renal function for transgender individuals including people on gender-affirming therapy, as well as best clinical practices in PrEP care for transgender populations.   

The author has no conflicts of interest to disclose.

View archived Clinical Research Update entries here.