Nephrolithiasis associated with renal insufficiency: factors predicting outcome.

BACKGROUND AND PURPOSE Renal calculous disease may be associated with various degrees of renal insufficiency secondary to a combination of obstruction, urinary infection, frequent surgical intervention, and coexisting medical disease. Herein, we present our data on the progression of renal function in patients with stones associated with renal insufficiency and assess the significance of various factors that could predict postoperative renal function deterioration. PATIENTS AND METHODS Data were obtained from 4400 patients undergoing treatment for calculous disease at our institute since 1991. Renal insufficiency, defined as a baseline serum creatinine >1.5 mg/dL, was present in 84 (1.9%). Predictive factors evaluated for renal function deterioration were preoperative (age, duration of symptomatology and nephrolithiasis, urinary tract infection, coexistent medical diseases, baseline serum creatinine, and stone burden), intraoperative (number of percutaneous tracts), and postoperative (recurrent infection, proteinuria, cortical atrophy, residual fragments, and stone recurrence). RESULTS Over a mean follow-up of 2.2 years (range 6 months-6 years), 33 patients (39.3%) showed improvement, 24 (28.6%) showed stabilization, and 27 (32.1%) showed deterioration in their renal function. Higher baseline serum creatinine, proteinuria >300 mg/day, renal cortical atrophy, stone burden >1500 mm(2), recurrent urinary infection, and age <15 years were significant predictors of subsequent renal function deterioration. CONCLUSIONS Patients with nephrolithiasis and mild to moderate renal insufficiency warrant aggressive treatment aimed at complete stone clearance and prevention of recurrence of stones and urinary infection. A higher baseline preoperative serum creatinine, proteinuria >300 mg/day on follow-up, renal cortical atrophy, stone burden >1500 mm(2), recurrent urinary infection, and age <15 years are associated with a significantly higher likelihood of renal function deterioration after treatment of the calculous disease.