Association of Race and Ethnicity With High Longevity Deceased Donor Kidney Transplantation Under the US Kidney Allocation System

Abstract

Rationale & objective: The US Kidney Allocation System (KAS) prioritizes candidates with ≤20% Estimated Post-Transplant Survival (EPTS) for high longevity kidneys defined by a ≤20% Kidney Donor Profile Index (KDPI). Use of EPTS in the KAS deprioritizes candidates with older age, diabetes, and longer dialysis durations. We assessed whether this use also disadvantages racial-ethnic minority candidates, who are younger but more likely to have diabetes and longer durations of kidney failure requiring dialysis.

Study design: Observational cohort study.

Setting: & Participants: Adult candidates for and recipients of kidney transplantation represented in the Scientific Registry of Transplant Recipients from January 2015 through December 2020.

Exposure: Race and ethnicity.

Outcomes: Age-adjusted assignment to ≤20% EPTS, transplantation of a ≤20% KDPI kidney, and post-transplant survival in longevity matched recipients by racial-ethnicity.

Analytic approach: Multivariable logistic regression, Fine-Gray competing risks survival analysis, and Kaplan-Meier and Cox Proportional Hazards methods.

Results: The cohort included 199,444 candidates (7% Asian, 29% Black, 19% Hispanic/Latino, 43% White) listed for deceased donor kidney transplantation. Non-White candidates had significantly higher rates of diabetes, longer dialysis duration, and were younger than White candidates. Adjusted for age, Asian, Black, and Hispanic/Latino candidates had significantly lower odds of having a ETPS score ≤20% (OR 0.86, [0.81, 0.91], 0.52 [0.50, 0.54], and 0.49, [0.47, 0.51]), and were less likely to receive a ≤20% KDPI kidney (subHR 0.70 [0.66, 0.75], 0.89 [0.87, 0.92], and 0.73 [0.71, 0.76]), compared to White candidates. Among recipients with ≤20% EPTS scores transplanted with a ≤20% KDPI deceased donor kidney, Asian and Hispanic recipients had lower post-transplant mortality (HR 0.45 [0.27, 0.77], and 0.63 [0.47, 0.86]) and Black recipients had higher but not statistically significant post-transplant mortality (HR 1.22 [0.99, 1.52]) compared to White recipients.

Limitations: Provider reported race-ethnicity data and 5-year post transplant follow-up period.

Conclusions: The US kidney allocation system is less likely to identify racial-ethnic minority candidates as having a ≤20% EPTS score which triggers allocation of high longevity deceased donor kidneys. These findings should inform the OPTN about how to remedy racial/ethnic disparities introduced through KAS's current approach of allocating allografts with longer predicted longevity to recipients with longer estimated post-transplant survival.