Compensatory Structural and Functional Adaptation after Nephrectomy in Obese Patients According to Waist Circumference

Abstract Objectives To investigate whether the postnephrectomy renal adaptation mechanism, focused on functional hyperfiltration as well as structural hypertrophy, was affected by abdominal obesity. Methods We retrospectively evaluated 358 patients who underwent simple or radical nephrectomy and nephroureterectomy between 2009 and 2013. Patients were classified according waist circumference, with values >102 cm in men and >88 cm in women considered high (obesity). Functional renal volume was measured using computed tomography performed preoperatively and 6 months postoperatively to evaluate the degree of remnant kidney hypertrophy. The degree of hyperfiltration was calculated from the difference between the preoperative and postoperative glomerular filtration rate/functional renal volume. Results The mean preoperative glomerular filtration rate, functional renal volume, and glomerular filtration rate/functional renal volume were 72.1 mL/min/1.73m2 , 282.8 cm3 , and 0.25 mL/min/1.73m2 /cm3 , respectively. The percent glomerular filtration rate reduction was significantly greater in the high waist circumference group (high, 25.9% vs. normal, 16.0%, p=0.036), although the degree of hypertrophic volume in the remnant kidney showed no difference. The change in glomerular filtration rate/functional renal volume was statistically lower in the high waist circumference group (high, 25.7% vs. normal, 40.2%, p=0.009). The factors associated with postoperative increased glomerular filtration rate/functional renal volume were low preoperative glomerular filtration rate, proteinuria, high predictive preserved functional parenchymal volume ratio, absence of hypertension, increased levels of high-density lipoprotein cholesterol, and normal waist circumference (all p