Moving toward Racial Equity in Preemptive Listing for Kidney Transplant in the United States

The benefits of preemptive kidney transplantation are extensive and well documented. Despite this, preemptive transplant accounts for only 10% of all deceased donor kidney transplants and <40% of all living donor kidney transplants.¹ While the prevalence of preemptive kidney transplantation increased following the Organ Procurement and Transplantation Network Kidney Allocation System in 2014, recent studies identified increased disparities in access to preemptive transplant for patients of non-White race and those with lower educational attainment and public insurance.² Proposed strategies to improve equity in access to preemptive waitlisting and kidney transplant include patient–clinician and center-level interventions such as educating primary care and nephrology clinicians about the benefits of preemptive waitlisting, improved treatment modality counseling, and simplifying the transplant evaluation process.

Another potential effective strategy toward attenuating disparities in the preemptive listing process may be to include a system-level adjustment to how waittime is accrued before dialysis initiation. The report by the National Academies of Medicine recommended the OPTN eliminate predialysis waiting time points from the kidney allocation system, so the date on which the patient begins regularly administered dialysis be the basis for accumulating points on the basis of waittime.³ However, preemptive care for patients with kidney failure has substantial benefits for patients, and the unfortunate disparities that exist in care of patients with kidney disease exist before the waitlist process and among patients receiving maintenance dialysis.^4,5 Thus, strategies that both improve preemptive listing while attenuating disparities seem to have the greatest potential health benefits in an equitable system.

The kidney failure risk equation (KFRE) was developed in 2011 on the basis of two Canadian cohorts of patients with CKD stages 3–5.⁶ It has been validated in multiple international cohorts, demonstrating its value in predicting the risk of CKD progression to kidney failure.⁷ In this issue of CJASN, Ku et al. studied a retrospective cohort of 1290 adults with eGFR <30 as defined by the Chronic Kidney Disease Epidemiology Collaboration calculation between 2012 and 2019.⁸ They compared the association of simulating allocation priority status for preemptive listing on the basis of a KFRE of 25% (i.e., 25% probability of the need for KRT within 5 years) with the current standard of an eGFR of <20 to examine the relative effect on preemptive waittime accrual with a focus on racial and ethnic equity.⁸ On the basis of the analysis, the estimated time between an eGFR of 20 and eGFR of 5 was 6–10 months shorter for Black, Hispanic, and Asian patients, respectively. However, the use of the KFRE threshold of 25% to begin waittime accrual had two prominent effects: increased time accrued as preemptive and attenuated differences in Black and Hispanic patients, but not Asian and Pacific Islander patients.

This study highlights several important considerations for national policy– and health system–level interventions. First, there is an important need for accurate measurement of racial and ethnic identity, noting disparities across several distinct groups. In particular, Hispanic/Latino and Asian and Pacific Islander patients are too frequently omitted from discussions of disparities. Second, the study findings reinforce the notion that preemptive listing is still an important option to incentivize the most appropriate care delivery, and national policies should be carefully assessed for their effects on the rates of transplant among all groups. Finally, this study suggests that a single eGFR value may be insufficient to guide eligibility and prioritization for placement on the transplant waitlist, particularly given the significant implications to patient prognoses and access to transplantation. Advantages of the KFRE include incorporation of sex and age into the formula, and additional use of the eight-variable KFRE (this study used the four-variable KFRE, which requires less information but has lower predictive accuracy) may add to the ability to discriminate patients at risk for more rapid transition to kidney failure.

There are other features of the study that are important to acknowledge. It is concerning that even in health system data, the investigators were unable to use the eight-variable KFRE due to missing data. As resource constraints are a chronic lament of health care systems, using tools that may require manual entry as opposed to application programming interfaces (i.e., APIs) may be a significant barrier to implementation. This study also had notable differences between the study populations that may attenuate the generalizability of findings, including a younger median age among Black and Hispanic patients, and a higher prevalence of hypertension and diabetes as compared with the national preemptively waitlisted population. Importantly, the study findings indicated faster progression of CKD to kidney failure in Black patients, underscoring the need for upstream interventions in CKD care. Notably, the populations excluded from this study were systematically distinct from the study population (including an approximate two-fold mortality rate), thus, applying findings in alternative settings and populations are critically important to validate findings. It is also important to note that the predictive models converged when the end point was date of kidney failure or transplant. This may suggest the effect of using a KFRE versus GFR threshold has a differential benefit earlier in the CKD course.

Overall, this study highlights an important concept in a critical phase of care for patients with late-stage CKD. Efforts to extend the current findings to other populations, evaluate alternative adjusted models to identify preemptive priority status, and evaluate other interventions to attenuate long-standing disparities in care are critically important. The incorporation of adjusted models (as opposed to using single eGFR measures with known intrapatient and interpatient variability) is worthy of continued discussion. Determining which data are worthy of incorporation into models to predict progression to kidney failure more rapidly will be reliant on improving systematic data collection. Alternative strategies to waitlist prioritization can also be considered, including accrual of waittime at GFR <20 for all patients, or incorporation of speed of CKD progression into start of waittime accrual.

In summary, preemptive kidney transplant from both living and deceased donors remains the ideal treatment option for patients with advanced CKD.⁹ Worsening disparities in preemptive transplantation for patients with public insurance and those from minoritized groups in the post–kidney allocation system era are concerning. Although elimination of predialysis waiting time points from the kidney allocation system may minimize differences across patient groups at the population level, alternative system-level strategies should be considered that balance the need for equity in access with the undeniable benefit of preemptive transplant. The article by Ku et al. presents a promising alternative with adjustment to how waittime is accrued before dialysis initiation and continues the critical discussion of how multilevel efforts can address the numerous factors that perpetuate disparities in preemptive transplant.

Disclosures

L.M. McElroy reports research funding from American Surgical Association Foundation Award, National Institute on Minority Health and Health Disparities under Award Number U54MD012530 and 1 K08 MD017632-01, and Robert Wood Johnson Foundation Harold Amos Medical Faculty Development Award and role on Editorial Boards for American Journal of Surgery, American Journal of Transplantation, Annals of Surgery Open, and Clinical Transplantation. J.D. Schold reports consultancy for eGenesis and Sanofi Corporation; research funding from Department of Defense, Kidney Transplant Collaborative, NIH/NIDDK, and One Legacy Foundation; honoraria from eGenesis and Sanofi Inc.; advisory or leadership role as Data Safety Monitoring Board Member for Bristol Myers Squibb, UNOS Policy Oversight Committee, and Vice Chair of UNOS Data Advisory Committee; and speakers bureau for Sanofi.

Funding

L.M. McElroy: NIMHD (K08 MD017632-01).

Author Contributions

Writing – original draft: Lisa M. McElroy, Jesse D. Schold.

Writing – review & editing: Lisa M. McElroy, Jesse D. Schold.