CKD Progression From the Time of Estimated GFR-Based Waitlist Eligibility and Racial Disparities in Transplant Access.

RATIONALE & OBJECTIVE eGFR equations that incorporate a term for race assign a higher value to Black individuals compared to non-Black individuals not attributable to sex, age, or serum creatinine. This difference may contribute to racial disparities in kidney transplant access. We sought to 1) compare time from meeting a transplant eligibility threshold of eGFR ≤20 ml/min/1.73M2 to kidney failure with replacement therapy (KFRT) among Black, Hispanic, and White patients, and 2) assess the impact of incorporation of race into eGFR expressions on establishment of waitlist eligibility and time from eligibility to KFRT. STUDY DESIGN Retrospective cohort. SETTING & PARTICIPANTS Using the OptumLabs® Data Warehouse, we assembled a cohort of 40,042 White, 8,519 Black, and 3,569 Hispanic patients having at least one eGFR value between 20 and 60 mL/min/1.73m2 within the preceding two years and an incident outpatient eGFR of ≤20 ml/min/1.73m2 between 2008-2018, using the CKD-EPI equation that includes a term for race coded as Black or non-Black. We then re-assembled a Black patient cohort based on incident eGFR ≤20 ml/min/1.73m2 (n=11,269) estimated using the same CKD-EPI equation for Black patients but coding patients as non-Black. EXPOSURE Race/ethnicity. OUTCOME Time to KFRT. ANALYTICAL APPROACH Unadjusted and adjusted Fine-Gray models; linear regression to compute eGFR slopes. RESULTS By 3 years, the cumulative incidence of KFRT was 20.5% among White patients, 40.9% among Hispanic patients, and 36% among Black patients whose eGFR was estimated using a race term coded as Black and 28.7% among Black patients whose eGFR was estimated using a race term coded as non-Black. In fully adjusted analyses including 11,269 Black patients with an eGFR <20 ml/min/1.73m2 based on coding them as non-Black, KFRT risk remained greater among Black (HR 1.28; 95% CI, 1.15-1.43) and Hispanic (HR 1.66; 95% CI 1.18-2.31) than among White patients. Based on slopes of eGFR decline, coding Black patients as non-Black would allow earlier waitlist activation by an estimated median of 0.5 years [IQR 0.27-1.23]. LIMITATIONS Inability to exclude individuals who would not be kidney transplant candidates if comprehensively evaluated. CONCLUSIONS A uniform eGFR threshold provides less opportunity for being placed on the transplant waitlist among Black and Hispanic patients. For many Black patients, estimation of GFR as if their race category were non-Black would allow substantially earlier waitlisting but would not eliminate their shorter time to KFRT and reduced opportunity for preemptive transplantation compared to White patients.