Race-Modified Equations Estimating Renal Function and the Disparity in Partial Nephrectomy Use in Black Patients

Abstract

Purpose: Black patients with renal tumors are less likely to undergo partial nephrectomy (PN) despite a higher risk of chronic kidney disease (CKD). Racialized equations estimating glomerular filtration rate (eGFR) estimate a 15% to 20% higher renal function for Black patients as opposed to non-Black patients. Whether raced-modified eGFR equations affect the use of nephron-sparing surgery in Black patients has not yet been explored. Materials and Methods: This is a single-center, retrospective review of 6327 consecutive patients who underwent PN (n = 3533) or radical nephrectomy (RN) (n = 2794) from 2005 to 2020. Patients were asked to self-report their race preoperatively. We excluded patients with a tumor thrombus (n = 149). Data were dichotomized into Black patients (n = 654) and non-Black patients (n = 5673). Multivariable logistic regression analysis controlled for known factors associated with PN. The impact of the race-modified (2009CKD-EPI) and race-free (2021CKD-EPI-refit) equations on the distribution of patients across CKD stages was analyzed. Results: Among 6327 patients, 10.3% were Black patients. Black patients had higher comorbidity rates and lower preoperative eGFR than non-Black patients (P < .001). Black patients had lower overall PN rates than non-Black patients (49% vs 57%; P < .001), a finding that was most pronounced in the CKD stage 1 group (55.84% vs 67.43%; P = .0011). On multivariable logistic regression analysis, the Black race was associated with lower odds of PN (OR = 0.76 (0.61-0.96), P = .001). CKD-EPI-refit moved 27% of Black patients to a lower and more accurate CKD stage. Conclusions: Using a conventional race-modified equation potentially overestimated the renal function of 27% of Black patients who were restaged into worse CKD stages when using the race-free equation. While the surgical approach is multifactorial, race-modified equations may overestimate renal function in a significant portion of Black patients and explain some, but not all, of the observed lower utilization of nephron-sparing surgical approaches in Black patients.