Uric acid levels correlate with baseline renal function and high levels are a potent risk factor for postoperative chronic kidney disease in patients with renal cell carcinoma

Abstract

Purpose: We investigated the relationship between preoperative uric acid and the glomerular filtration rate preoperatively and postoperatively in patients with renal cell carcinoma.

Materials and methods: Included in study were 1,534 patients who underwent radical or partial nephrectomy for renal cell carcinoma between 1994 and 2008. Uric acid was measured preoperatively. The estimated glomerular filtration rate was calculated using the MDRD (Modification of Diet in Renal Disease) equation preoperatively and postoperatively within 7 days, and at 3 months, and 1 and 3 years. We looked for correlations of uric acid with the glomerular filtration rate, patient demographics and comorbidities. We also evaluated the predictive value of uric acid for the preoperative glomerular filtration rate and new onset chronic kidney disease, defined as a glomerular filtration rate of less than 60 ml/minute/1.73 m(2), after nephrectomy using multivariate regression analysis.

Results: Mean ± SD uric acid was 5.2 ± 1.5 mg/dl (range 1.3 to 11.3). Mean preoperative uric acid correlated with the preoperative glomerular filtration rate (r = -0.313, p <0.001) and was associated with prevalent chronic kidney disease. On multivariate regression analysis a decreased preoperative glomerular filtration rate correlated significantly with earlier year of surgery, older age, male gender, hypertension, high uric acid and larger tumors (each p <0.001). Hypertension, male gender and high body mass index correlated with high uric acid (each p <0.001). Older age (p <0.001), diabetes mellitus (p = 0.002), low preoperative glomerular filtration rate (p <0.001) and high preoperative uric acid (p = 0.002) were significant predictors of new onset chronic kidney disease 3 years after nephrectomy.

Conclusions: Increased preoperative uric acid was an independent predictor of a low preoperative glomerular filtration rate and new onset chronic kidney disease in patients with renal cell carcinoma who underwent nephrectomy.