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

Rationale & Objective

The US Kidney Allocation System (KAS) prioritizes candidates with a ≤20% estimated posttransplant survival (EPTS) to receive 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 race and ethnicity 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.

Outcome

Age-adjusted assignment to ≤20% EPTS, transplantation of a ≤20% KDPI kidney, and posttransplant survival in longevity-matched recipients by race and 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 or Latino, and 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 or Latino candidates had significantly lower odds of having a ETPS score of ≤20% (odds ratio, 0.86 [95% CI, 0.81-0.91], 0.52 [95% CI, 0.50-0.54], and 0.49 [95% CI, 0.47-0.51]), and were less likely to receive a ≤20% KDPI kidney (sub-hazard ratio, 0.70 [0.66-0.75], 0.89 [0.87-0.92], and 0.73 [0.71-0.76]) compared with White candidates. Among recipients with ≤20% EPTS scores transplanted with a ≤20% KDPI deceased donor kidney, Asian and Hispanic recipients had lower posttransplant mortality (HR, 0.45 [0.27-0.77] and 0.63 [0.47-0.86], respectively) and Black recipients had higher but not statistically significant posttransplant mortality (HR, 1.22 [0.99-1.52]) compared with White recipients.

Limitations

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

Conclusions

The US kidney allocation system is less likely to identify race and ethnicity minority candidates as having a ≤20% EPTS score, which triggers allocation of high-longevity deceased donor kidneys. These findings should inform the Organ Procurement and Transplant Network about how to remedy the race and ethnicity disparities introduced through KAS’s current approach of allocating allografts with longer predicted longevity to recipients with longer estimated posttransplant survival.

Plain-Language Summary

The US Kidney Allocation System prioritizes giving high-longevity, high-quality kidneys to patients on the waiting list who have a high estimated posttransplant survival (EPTS) score. EPTS is calculated based on the patient’s age, whether the patient has diabetes, whether the patient has a history of organ transplantation, and the number of years spent on dialysis. Our analyses show that Asian, Black or African American, and Hispanic or Latino patients were less likely to receive high-longevity kidneys compared with White patients, despite having similar or better posttransplant survival outcomes.