Albo, Giovanni A. Gonzalez

ObjectiveTo validate a new baseline estimated glomerular filtration rate (NB‐GFR) formula in a cohort of robotic‐assisted partial nephrectomies (RAPN).MethodsNB‐GFR = 35 + preoperative GFR (× 0.65) – 18 (if radical nephrectomy) – age (× 0.25) + 3 (if tumor size >7 cm) – 2 (if diabetes). NB‐GFR was calculated in 464 consecutive RAPN from a single surgeon cohort. 143 patients were excluded secondary to insufficient eGFR follow up. We analyzed NB‐GFR accuracy utilizing the last observed eGFR 3–12 months post RAPN. Categorical variables were summarized with the frequency and percentage of patients. Numerical variables were summarized with the median, 25th percentile, and 75th percentile.ResultsThe mean difference between observed and predicted NB‐GFR was 4.6 ml/min/1.73m2 (95% CI −6.9 to 16.1 ml/min/1.73m2). There was a pattern of higher observed NB‐GFRs being underestimated by the NB‐GFR equation while lower observed NB‐GFRs were overestimated by the NB‐GFR equation. The NB‐GFR formula had a high level of accuracy with 98.8% of predicted NB‐GFRs falling within 30% of the observed NB‐GFR (95% CI 86.8% to 99.5%). The median and interquartile range of the difference between observed and predicted NB‐GFR was 3.9 ml/min/1.73m2 (IQR 0.7 to 8.2 ml/min/1.73m2). The sensitivity, specificity, positive predictive value, and negative predictive value for the ability of predicted NB‐GFR to identify those with an observed NB‐GFR <60 ml/min/1.73m2 after RAPN was 98%, 92%, 88%, and 99%, respectively.ConclusionThe NB‐GFR equation developed with partial and radical nephrectomy cohorts is accurate in predicting post‐operative eGFR 3–12 months following RAPN.

Objective: To evaluate the association between preoperative statin use with changes in estimated glomerular filtration rate (eGFR) after robot-assisted partial nephrectomy (RAPN). Methods: Three hundred eighty-nine consecutive patients undergoing RAPN were evaluated. Associations of preoperative statin use with change in eGFR from pre-RAPN to postoperative day 1 (POD1), 1, 6, and 12 months after RAPN were evaluated using longitudinal mixed-effects regression models with random patient-specific intercepts and slopes while accounting for imbalance of preoperative patient and tumor characteristics between groups with stabilized inverse propensity score weighting. Postoperative eGFR change from baseline was measured as total change, maintaining eGFR within 10% of baseline, and as going from eGFR >60 mL/min/1.73 m 2 to <60 mL/min/1.73 m 2 . Results: One hundred sixty-seven (43.0%) of 389 patients were on statin therapy preoperatively. Statin patients were older (66 vs 58 years) and had higher rates of comorbidities, including diabetes mellitus (31.7% vs 14.9%) and hypertension (82.6% vs 45%). Statin patients tended to have lower preoperative eGFR (mean ± standard deviation, 71.1 ± 17.6 vs 77.4 ± 19.4 mL/min/1.73 m 2 ). There was no evidence of an association of preoperative statin use with changes in eGFR at any time point after RAPN ( p = 0.66). Conclusion: Patients on preoperative statins undergoing RAPN had lower eGFR preoperatively compared with those not taking those medications. There was no evidence of an association between preoperative statin use and change in post-RAPN eGFR in the immediate postoperative period or at 1 year after surgery.