Comparison of rates and risk factors for developing chronic renal insufficiency, proteinuria and metabolic acidosis after radical or partial nephrectomy

OBJECTIVE To investigate the incidence of and risk factors for developing chronic renal insufficiency (CRI), proteinuria and metabolic acidosis (MA) in patients treated with radical nephrectomy (RN) or nephron-sparing surgery (NSS). PATIENTS AND METHODS We retrospectively reviewed 749 patients (mean age 57.7 years; mean follow-up 6.4 years) who had RN or NSS for renal tumours between July 1987 and June 2006 at our institution. The demographics and outcomes were analysed and recorded. The primary outcome variable was the development of an estimated glomerular filtration rate (eGFR) of < 60 mL/min/1.73 m(2), with secondary outcomes being the development of a serum creatinine level of >= 2.0 mg/dL, MA (serum bicarbonate < 22 mmol/L), and proteinuria (>= 1+ on dipstick testing). Multivariate logistic regression (MV) was used to identify risk factors for developing an eGFR of < 60 mL/min/1.73 m(2), a creatinine level of >= 2.0 mg/dL and MA. RESULTS Of the 749 patients, 499 had RN and 250 NSS; there were no significant demographic differences between the groups. After surgery a significantly greater proportion of the RN than the NSS group had a low eGFR (44.7% vs 16.0%, P < 0.001), MA (12.8% vs 7.2%, P = 0.02), proteinuria (22.2% vs 13.2%, P = 0.003) and elevated creatinine (14.2% vs 8.4%, P = 0.022). MV showed that diabetes mellitus (odds ratio 8.96, P = 0.002), RN (5.32, P < 0.001), hypertension (4.55, P = 0.003), a body mass index (BMI) of >= 30 kg/m(2) (3.51, P = 0.017), age >= 60 years (2.91, P = 0.015) and smoking (2.44, P = 0.014) were risk factors for developing a low eGFR; and that age >= 60 years (2.00, P = 0.019), diabetes mellitus (10, P < 0.001), hypertension (7.41, P = 0.002), smoking (5.29, P < 0.001) and RN (3.08, P < 0.001) were risk factors for developing an elevated creatinine level; and that being male (2.50, P = 0.019), age >= 60 years (3.13, P = 0.002), a BMI >= 30 (3.52, P < 0.001), RN (9.82, P < 0.001), preoperative eGFR < 60 (9.71, P < 0.001) and elevated creatinine (5.9, P = 0.008) were risk factors for developing MA. CONCLUSIONS Patients undergoing RN had significantly greater CRI, MA and proteinuria rates than a well-matched group undergoing NSS. In addition to RN, age >= 60 years, diabetes mellitus, hypertension and smoking were associated with progression to CRI after surgery.