Kidneys recovered from Black deceased donors have been associated with higher discard rates. Now a new study presented at the 2023 American Transplant Congress finds that kidney discard rates are no worse among race groups once Kidney Donor Profile Index (KDPI) is taken into account.
“The higher overall discard of Black donor kidneys is observed due to the inclusion of a race coefficient in the KDPI, which systematically assigns a higher KDPI to Black donor kidneys,” according to Oshorenua Aiyegbusi, MBBS, of the University of British Columbia in Vancouver, and colleagues. “Therefore, more kidneys from Black donors are categorized as KDPI ≥85%, a threshold beyond which the majority of donated kidneys are discarded.”
Using the 2005-2018 Scientific Registry of Transplant Recipients, the investigators identified 169,638 kidneys recovered for transplantation. The overall rate of kidney discard was similar for Black and non-Black donors: 22% vs 18%.1
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The KDPI ranges from 0% to 100%. When investigators examined KDPI by deciles, kidney discard rates were lower for Black vs non-Black donors in both the Neurological Brain Dead (NBD) and Donation after Circulatory Death (DCD) cohorts. At a KDPI of 11%-20%, for example, the kidney discard rates were 1.1% vs 5.0% for Black vs non-Black donors in the DBD cohort and 0% vs 1.3%, respectively, in the DCD cohort. According to the investigators, the findings demonstrate that deceased donor source does not affect kidney utilization independent of the KDPI.
The KDPI is based on the Kidney Donor Risk Index (KDRI), which attributes a higher estimated risk for allograft failure to kidneys from Black donors. Approximately half of kidneys with a KDPI of 85% or more, the highest risk category, are discarded.
“The findings suggest that removing the race coefficient from the KDPI may increase the utilization of Black donor kidneys, which could increase the transplantation rate among Black donor wait-list candidates,” according to Dr Aiyegbusi and colleagues.
A 2023 study published in the American Journal of Transplantation found that removing the Black race variable decreases the proportion of Black donors with a KDPI more than 85% from 31.1% to 17.8%, which is close to the 15.7% rate for non-Black donors.2
According to the Organ Procurement & Transplantation Network, kidneys with a KDPI higher than 85% are expected to function for more than 5.5 years. Kidneys with KDPI of 21%-85% and ideally 0%-20% have longer estimated longevity of 8.9 and 11.4 years, respectively. 3
“As we seek an unbiased and more accurate and precise model toward eGFR, we must do the same to assess kidney donor quality to improve equity in kidney transplantation,” Samira Farouk, MD, a transplant nephrologist at the Icahn School of Medicine at Mount Sinai in New York, New York, wrote in an article in Kidney News, a publication of the American Society of Nephrology.4 Black race is a social construct not a biological one.
Some of the researchers suggested including apolipoprotein L1 (APOL1) genotype and possibly other high-risk kidney variants in the KDPI if studies confirm their association with early graft failure.
A 2023 study of 120,091 recipients of a first kidney, published in the Clinical Journal of the American Society of Nephrology, found that preemptive receipt of a kidney with a KDPI of 85 or higher carried a 1.5-fold increased risk for graft failure, comparable to the 1.6-fold increased risk associated with nonpreemptive receipt of a KDPI 51%-84% kidney, using a nonpreemptive low KDPI kidney scored 20% or less as the reference.5
Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original references for a full list of authors’ disclosures.
References
1. Aiyegbusi O, Chang D, Fakhredine S, Gill J. Black donor race and deceased donor kidney utilization. Presented at: ATC 2023; June 3-7, San Diego, California. Abstract 310.
2. Miller J, Lyden GR, McKinney WT, Snyder JJ, Israni AK. Impacts of removing race from the calculation of the kidney donor profile index. Am J Transplant. 2023 May;23(5):636-641. doi:10.1016/j.ajt.2022.12.016
3. Kidney Donor Profile Index (KDPI) guide for clinicians. OPTN. Accessed on May 19, 2023.
4. Farouk S. Reenvisioning the Kidney Donor Risk Index without Race. ASN Kidney News; January 1, 2022.
5. Kadatz MJ, Gill J, Gill J, et al. The benefits of preemptive transplantation using high-Kidney Donor Profile Index Kidneys. Clin J Am Soc Nephrol. Published online April 7, 2023. doi:10.2215/CJN.0000000000000134
