#3804 association between plasma xor and outcomes in ckd patients

Abstract Background and Aims Plasma xanthine oxidoreductase (pXOR) is an enzyme plays a key role in uric acid (UA) production and produces reactive oxygen species (ROS), and it has been reported that pXOR activity is related with cardiovascular events in the general population. However, the relationship between pXOR activity and prognosis in patients with chronic kidney disease (CKD) remains unclear. Method We measured pXOR activity by Liquid chromatography tandem quadruple mass spectrometer (LC-TQMS method) in 415 outpatients with CKD, and compared demographic and laboratory data between two groups based on the median pXOR activity. Furthermore, we examined the association between pXOR activity and outcomes; renal replacement therapy (RRT), major adverse cardiovascular events (MACE), and all-cause mortality, using multivariate Cox proportional hazards model. Results Median age and eGFR were 71 years old and 21.6 ml/min/1.73 m2, respectively. Median pXOR activity is 3.33 pmol/h/ml and 26.3 pmol/h/ml in the lower and higher pXOR activity groups, respectively. eGFR was significantly lower and UA was significantly higher in the lower pXOR activity group compared with the higher pXOR group (eGFR, 18.9 vs 27.4, P, <0.001; UA, 5.7 vs 6.1, P, <0.001). During the follow-up period of 38 months, the incidence of each outcome including RRT, MACE, or all-cause mortality were significantly higher in the lower pXOR group (log rank test, P<0.001). Multivariate Cox proportional hazards analysis including eGFR and UA levels showed that lower pXOR activity was significantly associated with poor renal? outcome (HR, 1.4; 95% CI, 1.0-2.1; P, 0.038). Furthermore, in subgroup analysis with or without antihyperuricemic use, univariate Cox analysis showed similar association between pXOR and each outcome. Conclusion In patients with CKD, lower pXOR activity has a significantly higher risk of all outcome (RRT, MACE, and all-cause mortality).