Race‐free renal function estimation equations and potential impact on Black patients: Implications for cancer clinical trial enrollment

Abstract

Background Black patients face disparities in cancer outcomes. Additionally, Black patients are more likely to be undertreated and underrepresented in clinical trials. The recent recommendation to remove race from the estimated glomerular filtration rate (eGFR) results in lower eGFR values for Black patients. The ramifications of this decision, both intended and unintended, are still being elucidated in the medical community. Here, the authors analyze the removal of race from eGFR for Black patients with cancer, specifically with respect to clinical trial eligibility. Methods In a cohort of self‐identified Black patients who underwent nephrectomy at a tertiary referral center from 2009 to 2021 (n = 459), eGFR was calculated with and without race in commonly used equations (Chronic Kidney Disease Epidemiology Collaboration [CKD‐EPI] and Modification of Diet in Renal Disease [MDRD]). The distribution of patients and changes within chronic kidney disease stages with different equations was considered. Theoretical exclusion at commonly observed clinical trial eGFR points was then simulated on the basis of the utilization of the race coefficient. Results The median eGFR from CKD‐EPI was significantly higher with race (76 ml/min/1.73 m2) than without race (66 ml/min/1.73 m2; p < .0001). The median eGFR from MDRD was significantly higher with race (71.0 ml/min/1.73 m2) than without race (58 ml/min/1.73 m2; p < .0001). Observing results in the context of common clinical trial cutoff points, the authors found that 13%–22%, 6%–12%, and 2%–3% more Black patients would fall under common clinical trial cutoffs of 60, 45, and 30 ml/min, respectively, depending on the equation used. A subanalysis of stage III–IV patients only was similar. Conclusions Race‐free renal function equations may inadvertently result in increased exclusion of Black patients from clinical trials. This is especially concerning because of the underrepresentation and undertreatment that Black patients already experience. Plain Language Summary Black patients experience worse oncologic outcomes and are underrepresented in clinical trials. Kidney function, as estimated by glomerular filtration rate equations, is a factor in who can and cannot be in a clinical trial. Race is a variable in some of these equations. For Black patients, removing race from these equations leads to the calculation of lower kidney function. Lower estimated kidney function may result in more black patients being excluded from clinical trials. The inclusion of all races in clinical trials is important for offering best care to everyone and for making results from clinical trials applicable to everyone.

Urological impact of race-free estimated glomerular filtration rate equations

“…For patients with cancer, it would impact the cross-sectional imaging in diagnosing or staging and the type of urinary diversion following cystectomy, increasing the number of Black individuals ineligible for chemotherapy or those recommended to receive less than a full dose or a potentially less accurate dose adjustment (by 61%-163%) for several chemotherapies, which may lead to decreased quality of life and survival ( 8 ), thereby worsening the already prevalent racial disparities in healthcare. Furthermore, this might intensify the ongoing issue of underrepresentation by potentially increasing the exclusion of Black patients from clinical trials ( 9 ).…”

Evaluation of a Non–race-based Equation in Predicting Glomerular Filtration Rates Postnephrectomy in a Racially Diverse Cohort

“…2 The removal of this coefficient has exhibited median eGFR decreases of 10-14 mL/min/1.73 m 2 among Black patients. 3,4 While laudable, the decision to remove race from eGFR and its effect on renal function assessment has considerable implications and potential consequences that should be thoroughly explored. 3,4…”

“…3,4 While laudable, the decision to remove race from eGFR and its effect on renal function assessment has considerable implications and potential consequences that should be thoroughly explored. 3,4…”

Reply by Authors

“…Indeed, up to 13%, 6%, and 2% more Black patients following nephrectomy would fall under common cutoffs of 60, 45, and 30 mL/min/1.73 m 2 when transitioning from the 2009 race-based to the 2021 non–race-based chronic kidney disease Epidemiology Collaboration equation. 3…”

“…Indeed, up to 13%, 6%, and 2% more Black patients following nephrectomy would fall under common cutoffs of 60, 45, and 30 mL/min/1.73 m 2 when transitioning from the 2009 race-based to the 2021 noneracebased chronic kidney disease Epidemiology Collaboration equation. 3 While these changes are laudable, the unintended consequences should be examined. Alternatives, such as cystatin Cebased equations, which are less susceptible to muscle mass changes and do not consider race, should be explored.…”