Impact of Race-Adjusted Glomerular Filtration Rate Estimation on Eligibility for Simultaneous Liver-Kidney Transplantation

Abstract

Estimated glomerular filtration rate (eGFR) is adjusted for Black race in commonly used formulas. This has potential implications for access to simultaneous liver-kidney transplantation (SLKT) as qualifying criteria rely on eGFR. We performed a retrospective study of United Network for Organ Sharing national transplant registry data between February 28, 2002, and March 31, 2019, to evaluate the proportion of Black patients who would be reclassified as meeting SLKT criteria (as defined per current policies) if race adjustment were removed from 2 prominent eGFR equations (Modification of Diet in Renal Disease-4 [MDRD-4] and Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]). Of the 7937 Black patients listed for transplant during the study period, we found that 3.6% would have been reclassified as qualifying for chronic kidney disease (CKD)-related SLKT with removal of race adjustment for MDRD-4, and 3.0% would have been reclassified with CKD-EPI; this represented 23.7% and 18.7% increases in SLKT candidacy, respectively. Reclassification impacted women more than men (eg, 4.5% versus 3.0% by MDRD-4; P < 0.05). In an exploratory analysis, patients meeting SLKT criteria by race-unadjusted eGFR equations were significantly more likely to receive liver transplantation alone (LTA) compared with SLKT. Approximately 2.0% of reclassified patients required kidney transplantation within 1 year of LTA versus 0.3% of nonreclassified patients. In conclusion, race adjustment in eGFR equations may impact SLKT candidacy for 3.0% to 4.0% of Black patients listed for LTA overall. Approximately 2.0% of patients reclassified as meeting SLKT criteria require short-term post-LTA kidney transplantation. These data argue for developing novel algorithms for glomerular filtration rate estimation free of race to promote equity.

Figure 1 –. Impact of Race Adjustment on Distribution of Minimum Waitlist eGFR among Black Patients Listed for Liver Transplantation (2002–2019) for (A) MDRD-4 and (B) CKD-EPI Equations

Panel A: Differences in the distribution of minimum eGFR among Black patients during waitlisting as calculated by MDRD-4 with and without the race adjustment term. Panel B: Differences in the distribution of minimum eGFR among Black patients during waitlisting as calculated by CKD-EPI with and without the race adjustment term. In both Panels A and B, there are significant differences in the distributions such that race adjustment shifts eGFR towards higher values. Note: the above distributions do not include GFR values for patients on dialysis, as these were designated as 0mL/min/1.73m² for all patients.

Figure 2 –. Difference in eGFR With and Without Race Adjustment for MDRD-4 and CKD-EPI Equations Across a Range of Serum Creatinine Values

Note: Difference in eGFR was computed as the race-adjusted (-R) estimate minus the race-unadjusted (-NR) estimate. The shaded region corresponds to the approximate creatinine range where eGFR ranges from 30–45mL/min/1.72m² for a hypothetical 55-year-old Black female, the region where decisions regarding simultaneous liver-kidney transplantation would be most relevant and impacted by race adjustment.