Predictors of Postoperative Decline in Estimated Glomerular Filtration Rate in Patients Undergoing Robotic Partial Nephrectomy

Abstract

To identify prognostic indicators of estimated glomerular filtration rate (eGFR) following robotic partial nephrectomy (RPN). In a retrospective study of RPN patients, we examined data describing age, gender, eGFR, body mass index (BMI), tumor size (TS), length of stay, and estimated blood loss (EBL). Changes in eGFR (i.e., renal function trajectory [RFT]) and chronic kidney disease (CKD) stage shift were analyzed with mixed model linear and logistic regression analyses, Chi-squared, and t-tests. Changes in eGFR (RFT) were determined in 122 patients at baseline and at 6- and 12-month follow-up visits. Mean age, TS, and Charlson comorbidity index (CCI) were 62±11 years, 3±1.2 cm, and 4.8±1.8, respectively. The pre- and postoperative eGFR was lower in patients >60 years. Preoperative eGFR was unrelated to gender, BMI>30 kg/m(2), histopathology, nuclear grade, and TS. Univariate analyses determined that age, BMI>30, EBL>200 mL, CCI>5, and TS were associated with greater declines in eGFR. Reduced eGFR was also associated with warm ischemia time ≥22 minutes, while age was associated with a ≥1 worsening of British CKD classification. Using multivariate analysis, only age was significantly associated with a decline in eGFR, which was greater in patients with a normal preoperative eGFR. Patient age, BMI>30, EBL>200 mL, CCI>5, and TS were predictors of greater postoperative declines in eGFR. Although a decline in eGFR was proportionally greater in low stage CKD, postoperative changes are associated with advancing age.