A NEW study published has raised important questions about how kidney function is measured in potential living kidney donors (LKDs). Researchers at the University of Minnesota found that differences in kidney function measurements, whether adjusted for body size or not, can impact long-term outcomes for donors.
The study examined 627 adult kidney donors between 2007 and 2023 who underwent measured glomerular filtration rate (mGFR) testing before donation. The research compared two ways of reporting kidney function: a non-indexed mGFR (absolute filtration rate) and a body surface area (BSA)-indexed mGFR (adjusted for body size).
Results showed that 90% of donors had mGFR values above the required threshold for donation using both methods (concordant group). However, 11% had sufficient kidney function according to the non-indexed value but fell below the threshold when adjusted for body size (discordant group). These discordant donors were more likely to be older (median age 54.1 versus 42.8 years) and have a higher body mass index (28.0 versus 26.1).
At one year post-donation, donors in the discordant group had lower kidney function, and they were over ten times more likely to develop a sustained low eGFR (<45 mL/min/1.73m²) compared to their concordant counterparts.
These findings suggest that kidney function measurements adjusted for body size may provide a better predictor of long-term kidney health in donors. However, there is no current consensus on which method should be used for donor eligibility, highlighting the need for further research to guide clinical decision-making.
Aleksandra Zurowska, EMJ
Reference
Abraham JM et al. Non-Indexed vs. Body Surface Area Indexed Measured Glomerular Filtration Rate Determinations as a Criterion of Living Donor Acceptance. CJASN. 2025;DOI: 10.2215/CJN.0000000606.
