Simplified PADUA renal (SPARE) nephrometry score validation and long-term outcomes after robot-assisted partial nephrectomy

Background: International guidelines suggest the use of anatomic scores to predict surgical outcomes after partial nephrectomy (PN). We aimed at validating the use of Simplified PADUA Renal (SPARE) nephrometry score in robot-assisted PN (RAPN). Materials and methods: Three hundred and sixty-eight consecutive RAPN patients were included. Primary endpoints were overall complications, postoperative acute kidney injury (AKI) and TRIFECTA achievement. Secondary endpoint was estimated glomerular filtration rate (eGFR) decrease at last follow-up. Multivariable logistic and linear regression models were used. Results: Of 368 patients, 229 (62%) vs. 116 (31%) vs. 23 (6.2%) harboured low- vs. intermediate- vs. high-risk renal mass, according to SPARE classification. SPARE score predicted higher risk of overall complications (Odds ratio [OR]: 1.23, 95%CI 1.09–1.39; P < 0.001), and postoperative AKI (OR: 1.20, 95%CI 1.08–1.35; P < 0.01). Moreover, SPARE score was associated with lower TRIFECTA achievement (OR: 0.89, 95%CI 0.81–0.98; P = 0.02). Predicted accuracy was 0.643, 0.614 and 0.613, respectively. After a median follow-up of 40 (IQR: 21–66) months, eGFR decrease ranged from -7% in low-risk to -17% in high-risk SPARE. Conclusions: SPARE scoring system predicts surgical success in RAPN patients. Moreover, SPARE score is associated with eGFR decrease at long-term follow-up. Thus, the adoption of SPARE score to objectively assess tumor complexity prior to RAPN may be preferable.