The Association of Rising Serum Uric Acid Levels with Survival in Renal Cell Carcinoma.

608 Background: To investigate the association of serum uric acid (SUA) levels along with statin use in Renal Cell Carcinoma (RCC), as statins may be associated with improved outcomes in RCC and SUA elevation is associated with increased risk of chronic kidney disease (CKD). Methods: Retrospective study of patients undergoing surgery for RCC with preoperative and postoperative SUA levels between 8/2005-8/2014. Increased SUA was defined as > 7mg/dL for males and > 5.7 mg/dL for females. Analysis was carried out between patients with increased postoperative SUA vs. patients with decreased/stable postoperative SUA. Kaplan-Meier analysis (KMA) calculated overall survival (OS). Multivariable analysis (MVA) was performed to identify factors associated with increased SUA levels and all-cause mortality. Results: 905 patients were analyzed. Decreased/stable SUA levels were noted in 675(74.6%) and increased SUA levels were noted in 230(25.4%). A higher proportion of patients with decreased/stable SUA levels took statins (27.9% vs 18.3%, p = 0.004). Increased SUA had significantly greater de novo CKD (38.7% vs. 18.4%, p < 0.001) and proteinuria (30.9% vs. 20.7%, p = 0.002). KMA demonstrated improved 5-year OS for patients with decreased/stable SUA compared to increased SUA for stage I, (93% vs. 60%), stage II (87% vs. 50%), and stage III (88% vs. 62%) RCC (all p < 0.001). MVA revealed that increasing BMI (OR 1.05, p = 0.009), statin use (OR 0.11, p < 0.001), dyslipidemia (OR 2.66, p = 0.004), stage III/IV cancer (OR 1.89, p = 0.015 and OR = 10.78, p < 0.001), and postoperative de novo CKD stage 3 (OR 5.95, p < 0.001) were predictors for increased postoperative SUA levels. MVA revealed increasing BMI (OR 1.09, p = 0.002), increasing SUA (OR = 4.70, p < 0.001), stage IV RCC (OR = 7.7, p < 0.001, and de novo CKD stage 3 (OR 7.07, p < 0.001) to be independent risk factors for worsened all-cause mortality. Conclusions: Increasing SUA post operatively was associated with worsened outcomes in RCC patients. Decreased SUA levels were associated with statin intake and lower stage disease as well as lack of progression to CKD and anemia. Further investigation is requisite.