Risk factors for progression of chronic kidney disease after robotic partial nephrectomy in elderly patients: results from a multi-institutional collaborative series

Background: Robotic partial nephrectomy (RPN) in patients ≥75 years is certainly underused with concerns regarding surgical quality and a negligible impact on renal function. The aim of this study was to identify predictors of progression of chronic kidney disease (CKD)for purely off-clamp (ocRPN) and on-clamp RPN (onRPN) in elderly patients on a multi-institutional series. Methods: A collaborative minimally-invasive renal surgery dataset was queried for "RPN" performed between July 2007 and March 2021 and "age≥75 years." A total of 205 patients matched the inclusion criteria. Descriptive analyses were used. Frequencies and proportions were reported for categorical variables while medians and interquartile ranges (IQR) were reported for continuous variables. Baseline, perioperative and functional data were compared between groups. New-onset of stages 3b,4,5 CKD in onRPN and ocRPN cohorts was computed by Kaplan-Meier analysis. Univariable and multivariable Cox regression analyses were performed to identify predictors of progression to severe CKD (sCKD [stages ≥3b]). For all statistical analyses, a two-sided P<0.05 was considered significant. Results: Mean age of the cohort considered was 78 years (IQR 76-80). At a median follow-up of 29 months (IQR 14.5-44.5), new onset CKD-3b and CKD-4.5 stages was observed in 16.6% and 2.4% of patients, respectively. At Kaplan-Meier analysis, onRPN was associated with a significantly higher risk of developing sCKD (P=0.002). On multivariable analysis, hypertension (HR 2.64; 95% CI 1.14-6.11; P=0.023), on-clamp approach (HR 3.41; 95% CI 1.50-7.74; P=0.003) non-achievement of trifecta (HR 0.36; 95% CI 0.17-0.78; P=0.01) were independent predictors of sCKD. Conclusions: RPN in patients≥75 years is a safe surgical option. On-clamp approach, hypertension and non-achievement of trifecta were independent predictors of sCKD in the elderly after RPN.