Predicting short- and long-term renal function following partial and radical nephrectomy.

Objectives: To externally validate the previously published Mayo clinic model for the prediction of early (<30 days) postoperative renal failure, which relies solely on preoperative estimated glomerular filtration rate (eGFR) and develop a novel model for the prediction of long-term (>30 days) renal function after partial nephrectomy (PN) and radical nephrectomy (RN), including patient factors and nephrometry scores.

Patients And Methods: Retrospective, single-center cohort study on patients who underwent PN or RN for a unilateral renal tumor between 2003 and 2019 with a preoperative eGFR of at least 15 ml/min/1.73m. Early postoperative renal failure was defined as eGFR <15 ml/min/1.73 m or receipt of dialysis within 30 days. We determined the area under the receiver operating characteristics curve (AUC) to assess the Mayo clinic model's discriminative power. We used hierarchical linear mixed models with backward selection of candidate variables to develop a prediction model for long-term eGFR following PN and RN, separately. Their predictive ability was quantified using the marginal and conditional R and an internal validation.

Results: We included 421 patients (7,548 eGFR observations) who underwent PN and 271 patients (6,530 eGFR observations) who underwent RN. The Mayo clinic model for prediction of early postoperative renal failure following PN and RN showed an AUC of 0.816 (95% CI 0.718-0.920) and 0.825 (95% CI 0.688-0.962), respectively. In multivariable models, long-term eGFR following PN was associated with age, diabetes, the presence of a solitary kidney, tumor diameter and preoperative eGFR, while long-term eGFR following RN was associated with age, body mass index, RENAL nephrometry score and preoperative eGFR. Marginal and conditional R were 0.591 and 0.855 for the PN model, and 0.363 and 0.849 for the RN model, respectively.

Conclusions: The Mayo clinic model for short-term renal failure prediction showed good accuracy on external validation. Our long-term eGFR prediction models depend mostly on host factors as opposed to tumor complexity and can aid in decision-making when considering PN vs. RN.