Performance of Future Glomerular Filtration Rate Equation by Race in a Large, Racially Diverse Patient Cohort Undergoing Nephrectomy for Renal Cell Carcinoma REPLY

OBJECTIVE:To examine the performance of the Palacios et al [Aguilar Palacios D, Wilson B, Ascha M, et al. New baseline renal function after radical or partial nephrectomy: a simple and accurate predictive model. J Urol. 2021;205:1310-1320] post-nephrectomy future glomerular function rate (fGFR) equation in a diverse cohort using both the Chronic Kidney Disease Epidemiology (CKD-EPI) 2009 equation with race, used in the creation of the formula, as well as the CKD-EPI 2021 equation without race. METHODS:Patients who underwent partial or radical nephrectomy for renal cell carcinoma from 2005-2021 were identified in our institutional database. Patients with creatinine values preoperatively and 3-12 months postoperatively were included. Correlation/bias/accuracy/precision of the fGFR equation (fGFR = 35+ [preoperative eGFR × 0.65] - 18 [if radical] - [age × 0.25] + 3 [if tumor >7 cm] - 2 [if diabetes]) with observed postoperative eGFR was determined by both the CKD-EPI-2021 and CKD-EPI 2009 equations. RESULTS:A total of 1443 patients were analyzed. Seventy-one percent (1024) were White and 22.9% (331) were Black. Most underwent radical nephrectomy (60.3%). 40% T3-T4 renal cell carcinoma (RCC), with 14.8% of patients having M1 disease. Median observed vs predicted fGFR was 58.0 vs 58.7 mL/min/1.73 m2 for CKD-EPI 2021 and 56.0 vs 57.5 for CKD-EPI 2009. For the total cohort, the correlation/bias/accuracy/precision of the fGFR equation was 0.805/-0.5/81.7/7.9-9.0 for CKD-EPI 2021 and 0.809/-0.8/81.3/-8.1 to 8 for CKD-EPI 2009. In Black patients, fGFR equation demonstrated >75% accuracy with both CKD-EPI equations; however, accuracy was lower in black patients with the CKD-EPI2021 equation (76.1% vs 83.4%, P = .003). CONCLUSION:The fGFR equation performed well in our large, diverse cohort, though accuracy was relatively lower when using CKD-EPI 2021 compared to CKD-EPI 2009.