Impact of Removing the Race Coefficient in Renal Function Estimate Equations on Drug Dosage Recommendations

Abstract

Background The appropriateness of including the race coefficient in glomerular filtration rate (GFR) equations in Black patients is debated, and the impact on drug dosing is unknown. Objective This study explored the impact of removing the race coefficient on drug dosing in Black patients in comparison to conventional methods. Methods This was a retrospective study of hospitalized patients who self-identified as Black/African American and were prescribed an antimicrobial that includes renal dosage recommendations in the product labeling. The primary end point was the discordance between drug dosing recommendations derived by body surface area deindexed GFR estimated by the CKD-EPI equation (Chronic Kidney Disease Epidemiology study) with and without race versus recommendations derived from Cockcroft-Gault (CG). Results A total of 210 Black patients were included. There was an 18% rate of discordance when GFR was estimated with the race coefficient (GFR w/Race) versus without the race coefficient (GFR w/out Race). GFR w/out Race had a higher level of agreement with dosing by creatinine clearance (CrCl; κ = 0.779) than GFR w/Race versus CrCl (κ = 0.651). GFR w/out Race had less within-patient difference than GFR w/Race in comparison to CrCl (mean difference: −6.3 vs −18.0 mL/min). Conclusions and Relevance This represents the first report to examine the removal of the race coefficient and its implication on drug dose discordance. GFR w/out Race had a higher level of agreement and less drug dose discordance than GFR w/Race, in comparison to CrCl estimates. If GFR equations are considered comparable to CrCl for the purposes of guiding drug dosing, GFR w/out Race should be considered.

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

“…Black patients experience great morbidity and mortality associated with CKD, have a 3–4 times higher risk of developing kidney failure, and have less access to treatments in comparison with White individuals 8 . The 16% decrease in eGFR from the removal of the race coefficient and the resulting higher CKD staging have considerable implications for the delivery of medical care 4,9 . For example, more Black patients may obtain a CKD diagnosis (eGFR < 60 ml/min/1.73 m 2 ) for closer monitoring; gain access to a nephrology referral (eGFR < 30 ml/min/1.73 m 2 ), medical nutrition therapy (eGFR = 13–50 ml/min/1.73 m 2 ), and kidney disease education (eGFR = 15–29 ml/min/1.73 m 2 ); and become eligible for kidney transplantation sooner (eGFR < 20 ml/min/1.73 m 2 ) 2,3 …”

“…8 The 16% decrease in eGFR from the removal of the race coefficient and the resulting higher CKD staging have considerable implications for the delivery of medical care. 4,9 For example, more Black patients may obtain a CKD diagnosis (eGFR < 60 ml/min/1.73 m 2 ) for closer monitoring; gain access to a nephrology referral (eGFR < 30 ml/min/1.73 m 2 ), medical nutrition therapy (eGFR = 13-50 ml/min/1.73 m 2 ), and kidney disease education (eGFR = 15-29 ml/min/1.73 m 2 ); and become eligible for kidney transplantation sooner (eGFR < 20 ml/min/1.73 m 2 ). 2,3 Although many effects of this change are beneficial, as described previously, the removal of race from eGFR has other consequences from an oncology perspective that must be examined.…”

“…The National Kidney Foundation and the American Society of Nephrology (NKF–ASN) have officially recommended excluding race from estimated glomerular filtration rate (eGFR) calculations to ameliorate these issues 1 . The resulting lower eGFR due to the removal of race has considerable implications for the delivery of medical care to Black patients, which range from earlier nephrology referral to increased kidney transplant eligibility 2–4 . However, the impact of removing race from eGFR has not been fully analyzed in the context of cancer care and oncology clinical trial eligibility.…”

“…1 The resulting lower eGFR due to the removal of race has considerable implications for the delivery of medical care to Black patients, which range from earlier nephrology referral to increased kidney transplant eligibility. [2][3][4] However, the impact of removing race from eGFR has not been fully analyzed in the context of cancer care and oncology clinical trial eligibility. A comprehensive understanding of the consequences of this change in oncology patients is important, especially because of the disparities that Black patients already experience in terms of cancer outcomes and representation in oncology clinical trials.…”

Contemporary considerations for nephrotoxin stewardship: Estimating kidney function and use of novel biomarkers

“…40 Non-indexed GFR means that eGFR values calculated by a formula an 18% rate of discordance when GFR was estimated with the race coefficient versus without the race coefficient. 41,42 All the aforementioned equations for calculating GFR rely on serum creatinine and have their own limitations. Serum cystatin C (CysC) is another endogenous filtration marker for eGFR.…”