The Significance of Follow-Up Serum Uric Acid Levels in Predicting All-Cause Mortality and Cardiovascular Mortality in Peritoneal Dialysis Patients

Abstract Background: Studies on the correlation between serum uric acid (SUA) and all-cause mortality in peritoneal dialysis (PD) patients were mainly based on the results of baseline SUA. We aimed to analyze the change of SUA level post PD, and the correlation between follow-up SUA and prognosis in PD patients. Methods: All patients who received PD catheterization and maintaining PD in our center from March 2, 2001 to March 8, 2017 were screened. Kaplan-Meier and Cox proportional-hazards regression models were used to analyze the effect of SUA levels on the risks of death. We graded SUA levels at baseline, 6 months, 12 months, 18 months and 24 months post PD by mean of SUA plus or minus a standard deviation as cut-off values, and compared all-cause and cardiovascular mortality among patients with different SUA grades. Results: A total of 1402 patients were included, 763 males (54.42%) and 639 females (45.58%). Their average age at PD start was 49.50±14.20 years. The SUA levels were 7.97±1.79mg/dl at baseline, 7.12±1.48mg/dl at 6 months, 7.05±1.33mg/dl at 12 months, 7.01±1.30mg/dl at 18 months, and 6.93±1.26mg/dl at 24 months. During median follow-up time of 31 (18, 49) months, 173 (12.34%) all-cause deaths occurred, including 68 (4.85%) cardiovascular deaths. There were no significant differences on all-cause mortality among groups with graded SUA levels at baseline, 12 months, 18 months and 24 months during follow-up or on cardiovascular mortality among groups with graded SUA levels at baseline, 6 months, 12 months, 18 months and 24 months during follow-up. At 6 months post PD，Kaplan Meier analysis showed there was significant difference on all-cause mortality among graded SUA levels (c2=11.315, P=0.010), and the all-cause mortality was lowest in grade of 5.65mg/dl≤SUA<7.13mg/dl. Conclusion: SUA level decreased during follow up post PD. At 6 months post PD, a grade of 5.65mg/dl≤SUA<7.13mg/dl was appropriate for better patients’ survival.