Validating the Palacios' future glomerular filtration rate equation with and without race.

616 Background: Accurate prediction of future glomerular function rate (fGFR) following nephrectomy in renal cell carcinoma (RCC) patients is of interest. A postoperative estimated glomerular filtration (eGFR) rate ≥ 45 mL/min/1.73m2 is considered favorable, with guidelines reflecting these findings. Though nephron sparing surgery is preferable, radical nephrectomy is often the preferred oncologic surgery. Various models to predict postoperative renal function have been proposed, with a new 2021 equation by Palacios et al. exhibiting strong performance in predicting fGFR. We aim to validate this fGFR equation in a large institutional 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, which is currently the recommended CKD-EPI creatinine equation. Methods: Using an institutional database, patients that underwent partial or radical nephrectomy for RCC from 2005-2021 were identified. Patients with creatinine values preoperatively and 3-12 months postoperatively were included, with end stage renal disease serving as exclusion criteria. Correlation/bias/accuracy/precision of the fGFR equation (fGFR=35+ [preoperative eGFR x 0.65]- 18 [if radical] - [age x 0.25]+ 3 [if tumor >7cm]-2 [if diabetes]) with observed postoperative eGFR was determined by both the CKD-EPI-2021 and CKD-EPI 2009 equations. Results: 1,443 patients were included in our analysis. 71% (1,024) and 22.9% (331) patients were white and black, respectively. A majority of patients underwent radical nephrectomy (60.3%). 40% of patients had T3-T4 RCC, with 14.8% of patients having M1 disease. Median observed vs predicted fGFR was 58.0 vs 58.7 ml/min/1.73m2 for CKD-EPI 2021 and 56.0 vs 57.5 for CKD-EPI 2009. 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/-8.1-8 for CKD-EPI 2009 equations (Table). Conclusions: The fGFR equation accurately predicted renal function in our large and diverse institutional cohort using both the CKD-EPI 2009 including race and CKD-EPI 2021 excluding race equations. [Table: see text]