Relationship between Serum Uric Acid Concentration and Acute Kidney Injury after Coronary Artery Bypass Surgery
An elevated serum concentration of uric acid may be associated with an increased risk of acute kidney injury (AKI). The aim of this study was to investigate the impact of preoperative uric acid concentration on the risk of AKI after coronary artery bypass surgery (CABG). Perioperative data were evaluated from patients who underwent CABG. AKI was defined by the AKI Network criteria based on serum creatinine changes within the first 48 hr after CABG. Multivariate logistic regression was utilized to evaluate the association between preoperative uric acid and postoperative AKI. We evaluated changes in C statistic, the net reclassification improvement, and the integrated discrimination improvement to determine whether the addition of preoperative uric acid improved prediction of AKI. Of the 2,185 patients, 787 (36.0%) developed AKI. Preoperative uric acid was significantly associated with postoperative AKI (odds ratio, 1.18; 95% confidence interval, 1.10-1.26; P<0.001). Adding uric acid levels improved the C statistic and had significant impact on risk reclassification and integrated discrimination for AKI. Preoperative uric acid is related to postoperative AKI and improves the predictive ability of AKI. This finding suggests that preoperative measurement of uric acid may help stratify risks for AKI in in patients undergoing CABG.