Association of Serum Uric Acid Concentration and Its Change with Cardiovascular Death and All-Cause Mortality

Abstract

Objective. There is no consensus on the role of abnormal uric acid (UA) levels in the prognosis of patients undergoing hemodialysis. We therefore aimed to investigate the effects of changes in UA concentration on the risk of all-cause death and cardiac death in such patients. Method. In this retrospective cohort study, patients admitted to two hemodialysis centers performing maintenance hemodialysis (MHD) in Wuhan First Hospital and Fourth Hospital Hemodialysis Center from January 1, 2007, to October 31, 2017, were included. Results. In all, 325 patients undergoing MHD aged 59.7±14.7 years, including 195 men (60%), were enrolled, with a median follow-up of 37 months. Serum UA (p<0.001) was significantly higher in the surviving group than in the death group. No significant difference was found in UA variability (p=0.193) between the two groups. Patients were assigned Quartile 1-Quartile 4 (from lowest to highest) based on serum UA levels. A total of 45 of 81 (55.6%) patients in Quartile 1 experienced all-cause death; 19 of 82 (23.2%) in Quartile 4 had all-cause mortality (OR, 0.2; 95% confidence interval, 0.1 to 0.5; p for trend<0.001). 25 of 81 (30.9%) in Quartile 1 had cardiac death; and 11 of 82 (13.4%) in Quartile 4 had cardiac death (OR, 0.3; 95% confidence interval, 0.2 to 0.8; p for trend=0.003). After adjusting for age, primary renal disease, vascular access, serum albumin, and UA variability, the OR values and 95% CI for all-cause death and cardiac death were 0.3 and 0.1-0.7 (p=0.001) and 0.6 and 0.2-1.4 (p=0.101), respectively. Additionally, the receiver operating characteristic curve showed that UA concentration and its changes combined with age had a good predictive value for all-cause mortality in patients undergoing MHD (AUC=0.7517, 95% CI: 0.6677-0.811, p=0.0245). However, the predictive value of cardiac death was not improved (AUC=0.7394, 95% CI: 0.6677-0.811, p=0.2194). Conclusion. Low UA levels were closely related to all-cause mortality in patients undergoing MHD. Although UA levels had no significant effect on cardiac death, they had a good predictive value for long-term prognosis in patients on MHD.