Living kidney donors with discordant kidney function measures had low post-donation eGFR
Key takeaways:
- Overall, 90% of living donors had non-indexed and body surface area indexed mGFR measurements above recommended thresholds.
- And 11% had body surface area indexed measurements below recommended thresholds.
Living kidney donors with discordant kidney function measures had lower eGFR after donation and a higher risk for eGFR counts below 45 mL/min/1.73 m2, researchers found.
“Living donor kidney transplantation is associated with superior outcomes compared to deceased donor kidney transplantation,” Abraham J. Matar, MD, a transplant surgery fellow at the University of Minnesota Department of Surgery and Transplant Division, wrote with colleagues. “Careful selection of living kidney donors is essential to minimizing the risk to the donor, including leaving adequate residual kidney function for long-term survival. Measurement of pre-donation kidney function is a critical component of the donor selection process and helps to predict both the amount of kidney function remaining following donation and the amount being transplanted into the recipient.”
The study sought to compare differences in non-indexed mGFR and body surface area indexed mGFR among living kidney donors, as well as relationships of these measures to post-donation eGFR.
Researchers examined data from 755 adults who made living kidney donors at the University of Minnesota from 2007 to 2023. Overall, 627 donors who had pre-donation measured GFR (mGRF) by iohexol plasma clearance and a minimum follow-up of 6 months post-donation were included.
Outcomes were eGFR 1 year after donation and sustained eGFR below 45 mL/min/1.73 m2.
Overall, 90% of living donors were identified as concordant: They had non-indexed and body surface area indexed mGFR measurements above recommended age-based thresholds. Researchers found 11% of living donors were discordant, having non-indexed measurements above the threshold while their body surface area indexed measurements were below it.
Researchers found discordant living donors were older, at a median age 54.1 years vs. 42.8 years for concordant donors and had a higher BMI of 28 kg/m2 vs. 26.1 kg/m2, respectively. Mean eGFR 1-year post-donation was higher for concordant living donors, according to the findings, but relative changes from pre-donation eGFR were similar between groups.
During a median 2.3 years of follow-up, 9% of discordant living donors had sustained eGFR levels below 45 mL/min/1.73 m² compared to 0.9% of concordant living donors. The hazard ratio for discordant measurements among donors was 10.7 (HR = 10.7; 95% CI, 3.21-35.6).
“Careful consideration should be given when assessing potential [living kidney donors] with large differences in their non-indexed and BSA-indexed mGFR, which may be pronounced in higher BMI and larger [body surface area] BSA patients,” Matar and colleagues wrote. Large multicenter studies “are needed to confirm our findings and determine whether pre-donation iohexol BSA-indexed vs. non-indexed mGFR measurements are better associated with late post-donation kidney function,” they added.
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