Uric acid: a novel risk factor for acute kidney injury in high-risk cardiac surgery patients?
Uric acid has been reported to be a risk factor for the development of chronic kidney disease; however, no study has examined whether uric acid may confer a risk for acute kidney injury. We investigated the relation between serum uric acid and the incidence of postoperative acute kidney injury in patients undergoing high-risk cardiovascular surgery (cardiac valve and aneurysm surgery). Following cardiovascular surgery, 18 of 58 patients (31%) developed acute kidney injury, with 11 of 24 (45.8%) in the elevated uric acid group (defined as >6 mg/dl) and 7 of 34 (20.5%) in the normal uric acid group (p = 0.05). After controlling for baseline renal function, left ventricular ejection fraction, use of nesiritide, type of surgery, and history of previous surgery, an elevated preoperative uric acid conferred a 4-fold risk for acute kidney injury (OR: 3.98, CI: 1.10-14.33, p = 0.035) and longer hospital stay (36.35 vs. 24.66 days, p = 0.009). This preliminary study suggests that uric acid may be a novel risk factor for acute kidney injury in patients undergoing high-risk cardiovascular surgery.