Performance of estimated glomerular filtration rate equations in Black living kidney donor candidates.

INTRODUCTION

New estimated glomerular filtration rate (eGFR) equations using serum creatinine and/or cystatin C have been derived to eliminate adjustment by perceived Black ancestry. We sought to analyze the performance of newer eGFR equations among Black living kidney donor candidates.

METHODS

Black candidates (n = 64) who had measured iothalamate GFR between January 2015 and October 2021 were included, and eGFR was calculated using race adjusted (eGFRcr2009 and eGFRcr-cys2012) and race unadjusted (eGFRcys2012, eGFRcr2021, and eGFRcr-cys2021) CKD-EPI equations. Bias and accuracy were calculated.

RESULTS

The eGFRcr2021 equation had a negative bias of 9 mL/min/1.73 m2 , while other equations showed a modest positive bias. Accuracy within 10% and 30% was greatest using the eGFRcr-cys2021 equation. With the eGFRcr2021 equation, 9.4% of donors with an mGFR > 80 mL/min/1.73 m2 were misclassified as having an eGFR < 80 mL/min/1.73 m2 . eGFR was also compared among 18 kidney donors at 6-24 months post-donation. Post-donation, the percentage of donors with an eGFR < 60 mL/min/1.73 m2 was 44% using the eGFRcr2021 equation compared to 11% using the eGFRcr-cys2021 equation.

CONCLUSION

The CKD-EPICr2021 equation appears to underestimate true GFR in Black living donor candidates. Alternatively, compared to CKD-EPICr2021, the CKD-EPICr-CysC2021 equation appears to perform with less bias and improved accuracy.