Lower time-averaged serum uric acid was associated with increased mortality in peritoneal dialysis patients.

Background: The relationship between time-averaged serum uric acid (TA-SUA) levels and prognosis in peritoneal dialysis (PD) patients are rarely discussed.

Methods: This was a retrospective cohort study. PD patients recruited from January 1, 2011, to December 31, 2020, were included. Baseline and follow-up uric acid levels over 1 year were collected to calculate time-averaged serum uric acid (TA-SUA) levels. Patients were divided into four groups based on TA-SUA quartiles: Q1 (<5.1 mg/dl), Q2 (5.1-5.8 mg/dl), Q3 (5.8-6.8 mg/dl), and Q4 (>6.8 mg/dl).

Results: A total 487 PD patients with a mean age of 52.0 ± 14.2 were enrolled, including114 (23.4%) diabetes. Q1 (n = 121, 24.8%), Q2 (n = 118, 24.2%), Q3 (n = 125, 25.7%), and Q4 (n = 123, 25.3%). The Q1 group exhibited characteristics of increased age, malnutrition, and a higher prevalence of diabetes. During the 48.1 months follow-up time, 197 (35.8%) died, 109 (55.3%) cardiovascular disease (CVD), 38 (19.3%) infections. Kaplan-Meier analysis revealed that both all-cause mortality and cardiovascular mortality were significantly higher in the Q1 and Q4 groups (log-rank = 24.373, p < 0.001). COX regression analysis showed that decreased TA-SUA level was an independent risk factor for all-cause mortality in PD patients after adjustment for confounding factors. Each 1 mg/dl decrease in TA-SUA level was associated with a 23.46% increase in all-cause mortality (HR = 0.81, 95% CI, 0.71-0.94; p = 0.004*). Lower serum albumin level was associated with increased all-cause mortality.

Conclusion: PD patients with lower TA-SUA were older and had a higher proportion of diabetes and malnourishment than those with higher TA-SUA. Long-term exposure to low TA-SUA levels was an independent predictor of all-cause and cardiovascular mortality in PD patients.