LOW URIC ACID CLEARANCE PREDICTS INCREASED CARDIOVASCULAR MORTALITY IN NORMOURECEMIC PERITONEAL DIALYSIS PATIENTS

Objective: Cardiovascular disease (CVD) is the leading cause of mortality in patients undergoing peritoneal dialysis (PD). While hyperuricemia is a known risk factor for cardiovascular morbidity, the role of uric acid (UA) clearance in predicting CVD outcomes remains unclear, particularly in normourecemic patients. We hypothesized that low UA clearance, even without elevated systemic UA levels, may influence CVD mortality. This study investigates the association between total UA clearance (tUACl) and CVD mortality in normourecemic PD patients.Design and method: A total of 155 PD patients, aged 52 (41-63) years with a dialysis vintage of 36 (17-58.5) months, who had been undergoing continuous ambulatory PD for at least 3 months before enrollment, were included in this prospective cohort study. tUACl was calculated as the sum of peritoneal and urinary UA clearances, based on daily UA excretion in dialysate and urine, respectively, and normalized to a BSA of 1.73 m2. CVD mortality was assessed over a 5-year follow-up period. Receiver operating characteristic (ROC) analysis determined the optimal tUACl threshold for predicting CVD mortality. Kaplan-Meier analysis and Cox regression, adjusted for age, gender, dialysis vintage, and comorbidities, evaluated the association between tUACl and CVD mortality. Results: During the five-year follow-up, 21 (13.5%) CVD-related deaths occurred. ROC curve analysis identified a tUACl threshold of 30 L/week/m2as the optimal predictor for CVD mortality (AUC=0.77, p=0.001). Kaplan-Meier analysis revealed a significant difference in CVD mortality between patients with tUACl above and below this threshold (Fig. 1). Furthermore, Cox regression analysis, adjusted for age, gender, dialysis vintage, and diabetes, showed that lower tUACl was independently associated with an increased risk of CVD mortality (HR=3.9, 95% CI 1.6-7.5, p=0.01). Conclusions: tUACl < 30 L/week/m2is independently associated with an increased risk of CVD mortality in normourecemic PD patients. These findings highlight the importance of monitoring UA clearance, even without hyperuricemia, as a potential predictor of CVD outcomes in PD patients. Further studies are needed to explore the mechanisms underlying this association and its clinical implications for improving patient management.