External Validation of a Predictive Model to Estimate Renal Function After Living Donor Nephrectomy.

BACKGROUND Transplantation from living donor nephrectomy (LDN) is the best treatment for end-stage renal disease, but observed decrease in donor renal function is a major concern. The aim of this study was to externally validate a predictive model to estimate 1-year postdonation eGFR and risk of chronic kidney disease (CKD) in living donors. METHODS All LDN performed at Necker Hospital from January 2006 to May 2018 were retrospectively included. Observed eGFR (using CKD-EPI formula) at 1-year post LDN was compared to the predicted eGFR calculated with a formula developed at Toulouse-Rangueil and based on predonation eGFR and age. Pearson correlation, receiver operating characteristics curve (ROC-curve) and calibration curve were used to assess external validity of the proposed prognostic model to predict postoperative eGFR and occurrence of CKD in donors. RESULTS 400 donors were evaluated with a mean postoperative eGFR of 62.1±14 ml/min/1.73m2. Significant correlation (Pearson r=0.66; p<0.001) and concordance (Bradley-Blackwood F=49.189; p<0.001) were observed between predicted and observed 1-year eGFR. Area under the ROC curve of the model relevant accuracy was 0.86 (CI 95% 0.82-0.89). CONCLUSIONS This study externally validated the formula to predict 1-year postdonation eGFR. The calculator could be an accurate tool to improve the selection of living kidney donor candidate.