Reclassification of CKD in living kidney donors with the refitted race-free eGFR formula

Race-modified estimated glomerular filtration rate underestimates chronic kidney disease prevalence in Black patients undergoing partial and radical nephrectomy: Implications for surgical planning

Introduction

In estimated glomerular filtration rate equations (eGFR), the race multiplier (RM) yields greater eGFR values and may assign less severe chronic kidney disease (CKD) stages to black individuals. When deciding on appropriateness for partial nephrectomy (PN), patients with CKD are often considered a relative or absolute indication. We hypothesize that the eGFR RM may have ramifications for patients being counseled for radical nephrectomy (RN) versus PN to manage their renal tumor.

Methods

We utilized prospective and retrospective, IRB-approved single-center databases to select patients who underwent PN or RN between 2016 and 2022. Demographics, preoperative risk factors, preoperative eGFR, and surgical management were collected. Descriptive statistics and two-tailed difference of proportion tests compared the percentage of patients with CKD who underwent nephrectomy.

Results

This cohort included 1137 patients who underwent RN or PN, including 74 (6.5%) Black patients and 93.5% (n = 1063) non-Black patients. There was no statistically significant difference between the eGFR of Black and non-Black individuals using the Modification of Diet in Renal Disease equation (P = 0.24) or Chronic Kidney Disease Epidemiology Collaboration 2009 (CKD-EPI 2009) (P = 0.45); however, there was statistically significant difference in eGFR between sample populations when using CKD-EPI 2021 (P = 0.0055). Of the Black patient cohort, 16.2% of patients reclassified to a worse CKD class using CKD-EPI 2021, including 9.5% of Black patients reclassified to CKD3a or worse, and 14.6% of all patients (Black and non-Black) reclassified to a different CKD class under the CKD-EPI 2021 equation.

Conclusions

There are quantitative differences in the evaluation of eGFR when utilizing different equations that may impact clinical considerations and health equity outcomes for nephrectomy across racial groups.

Clinical Impacts of Implementing the 2021 Race-Free Chronic Kidney Disease Epidemiology Collaboration Estimated Glomerular Filtration Rate

BACKGROUND

Estimated glomerular filtration rate (eGFR) has become incorporated into multiple clinical management situations. Historically, equations included a Black race coefficient, which lacked biological plausibility and created potential to exacerbate health disparities. A new equation created in 2021 changed the weighting of age, sex, and creatinine by modeling against a diverse cohort and removing the Black race coefficient.

CONTENT

A variety of clinical outcomes including kidney disease risk stratification, medication dosing, patient eligibility for clinical trials, and kidney donation are impacted by implementation of the new equation. Nearly 2 years after its initial publication, many studies have reported on observed analytical performance of the 2021 eGFR determined as diagnostic concordance and percentage of estimates within 30% of measured GFR. Additionally, the potential clinical impacts following adoption of the new eGFR among different patient populations has also been reported. Here we review these studies with a focus on assessing the data associated with the transition from 2009 to 2021 Chronic Kidney Disease Epidemiology Collaboration equations.

SUMMARY

The reported interindividual variation in eGFR performance is significantly larger than any potential benefit derived from race coefficients. Both the 2021 eGFR and the 2009 eGFR analytical performance fall short of the validation cohort performance in most cohorts. However, the 2021 analytical is similar or better than the 2009 eGFR in most cohorts. Implementing the 2021 eGFR will remove a systematic overestimation of kidney function among Black patients.

Mitigating Health Disparities in Transplantation Requires Equity, Not Equality

Despite decades of research and evidence-based mitigation strategies, disparities in access to transplantation persist for all organ types and in all stages of the transplant process. Although some strategies have shown promise for alleviating disparities, others have fallen short of the equity goal by providing the same tools and resources to all rather than tailoring the tools and resources to one's circumstances. Innovative solutions that engage all stakeholders are needed to achieve equity regardless of race, sex, age, socioeconomic status, or geography. Mitigation of disparities is paramount to ensure fair and equitable access for those with end-stage disease and to preserve the trust of the public, upon whom we rely for their willingness to donate organs. In this overview, we present a summary of recent literature demonstrating persistent disparities by stage in the transplant process, along with policies and interventions that have been implemented to combat these disparities and hypotheses for why some strategies have been more effective than others. We conclude with future directions that have been proposed by experts in the field and how these suggested strategies may help us finally arrive at equity in transplantation.