Identifying the predictors of estimated glomerular filtration rate after partial nephrectomy with a nonlinear regression model

Abstract

Purpose To evaluate the effect of partial nephrectomy on renal function and to identify predictors of estimated glomerular filtration rate (eGFR) at 6 months after partial nephrectomy. Methods Medical data of 154 consecutive patients who underwent partial nephrectomy for a renal mass between January 2015 and March 2020 were retrospectively analysed. The primary outcome measure was eGFR at 6 months postoperatively. An ordinary least regression analysis using a restricted cubic spline for continuous variables was performed to examine the association between primary outcome measure and candidate predictors. Results Of the patients, 66 (42.9\%) were females and 88 (57.1\%) were males with a median age of 60 (range, 50 to 67) years. The median baseline eGFR was 90.40 (range, 74.96 to 102.97) mL/min/1.73 m(2), while the median eGFR at 6 months was 77.12 (range, 61.06 to 91.93) mL/min/1.73 m(2) (P < .001). Baseline eGFR (regression coefficient (beta) = 22.7, 95\%CI: 18.8 to 26.5, P < .001) was found to be most significant predictor with the postoperative eGFR levels at 6 months. In addition, advanced tumour size (beta = -3.17, 95\%CI: -5.33 to -1.01, P < .001) and presence of hypertension (beta = -3.48, 95\%CI: -6.96 to -0.003, P = .049) were also found to be inversely associated with the postoperative eGFR levels at 6 months. Conclusion Baseline eGFR values, tumour size, and presence of hypertension are significant predictors of eGFR values in the mid-term in patients undergoing partial nephrectomy.