Correlation analysis of low-level serum uric acid and cardiovascular events in patients on peritoneal dialysis

Background The impact of serum uric acid (SUA) on development of cardiovascular disease (CVD) in patients undergoing peritoneal dialysis (PD) remains controversial, especially the impact of hypouricemia (HUA) on CVD. The aim of our study was to investigate the influence of low-level SUA on cardiovascular (CV) events in PD patients. Methods A retrospective cohort study was conducted.728 PD patients from February 1, 2010 to May 31, 2019 were enrolled. All demographic and laboratory data were collected at baseline and 6 months after PD treatment. The study cohort was divided into four groups according to SUA level (mu mol/L) after 6 months of PD: Group1 (< 360), Group2 (360-420), Group3 (420-480), Group4 (>= 480). The clinical characteristics of each group were analyzed. With Group2 as reference, logistic regression analysis was performed to investigate the correlation between SUA levels and risk of CV events in patients undergoing PD. Use Kaplan-Meier method to generate CV events risk graph. Results 728 patients were enrolled in this study, including 403 (55.4%) males and 325 (44.6%) females, with an average age of 48.66 +/- 13.98 years; of which 158 (21.7%) patients developed CV events. Multivariate COX regression showed that after adjusting for multiple clinical factors, Group1 (HR = 1.92, 95% CI 1.17-3.15, P = 0.01), Group3 (HR = 1.89, 95% CI 1.13-3.15, P = 0.015), and Group4 (HR = 2.38, 95% CI 1.35-4.19, P = 0.003) are all independent risk factors for developing CV events. The Kaplan-Meier risk curve of CV events showed that the risk of CV events in the Group1, Group3 and Group4 were significantly higher (Log-Rank = 12.67; P = 0.005). Restricted cubic spline (RCS) showed that SUA level is non- linearly associated with the risk of CV events, showing an U-shaped curve (chi(2)(4) = 13.3 P = 0.01). Conclusions Our study suggested that patients with SUA level less than 360 mu mol/L also exhibited the higher risk for developing CV events, an U-shaped association between SUA level and risk of CV events in patients undergoing PD. Both SUA levels below 360 mu mol/L and above 420 mu mol/L were found to be significant risk factors for developing CV events in patients undergoing long-term PD.