#2715 Evaluation of the effect of hemodialysis on serum uric acid levels and the association with cardiovascular diseases in patients with chronic kidney disease

Abstract Background and Aims Hyperuricemia, characterized by elevated serum uric acid (SUA) levels, is associated with a number of diseases, including chronic kidney disease (CKD) and end-stage renal disease (ESRD). The aim of this study was to assess the prevalence of hyperuricemia in CKD patients on hemodialysis (HD), to evaluate the effect of HD on SUA levels, and to determine the association with cardiovascular diseases. Method A cross-sectional study was performed involving 52 ESRD patients from two outpatient dialysis centers. SUA levels were measured, and data on HD adequacy over the past six months, preservation of water excretion kidney function, and interdialytic weight gain over the past month were analyzed. Statistical data processing was performed using the χ²-test, mean comparison, and regression analysis. Results The mean age of the patients was 56.50 ± 13.35 years, with 29 males (56.9%) and 22 females (43.1%). The prevalence of hyperuricemia, using the common cut-off point of 360 µmol/L, was 57.69%, including 58.06% in males and 57.14% in females. The mean dialysis vintage was 12.50 ± 62.22 months. None of the patients received urate-lowering therapy. Using the χ² criterion, a statistically significant difference in the prevalence of hyperuricemia (Fig. 1) was found depending on dialysis vintage (p 0.029), with peak values observed at the initiation of renal replacement therapy and after five years (61.54%). All patients with a dialysis vintage of 24–36 months had hyperuricemia, whereas the lowest hyperuricemia prevalence was observed in the 12–24-month group (16.67%), and no patients in the 36–60-month group had elevated SUA levels. Based on a minimum SUA value of 113 µmol/L and a maximum of 544 µmol/L, four quartiles were identified: Q1—SUA level from 113 to 309.5 µmol/L; Q2—SUA level from 309.5 to 374.0 µmol/L; Q3—SUA level from 374.0 to 420.75 µmol/L, and Q4—SUA level from 420.75 to 544 µmol/L. Statistically significant differences were found in the prevalence of prior acute cerebrovascular events (ACVE) or myocardial infarction (MI) depending on a SUA level (p 0.029) in CKD patients. The highest prevalence (50.0%) was observed in Q1, suggesting a higher prevalence of prior ACVE or MI in ESRD patients with relatively low SUA levels. High SUA levels in Q4 were not associated with an increased frequency of prior ACVE or MI (7.69%), which could contradict the expected association between hyperuricemia and cardiovascular risks. However, the primary limiting factor in this situation is the maximum SUA value of 544 µmol/L, which does not allow for a complete assessment of this association. A regression analysis was also performed to assess the effect of dialysis vintage (R² 0.003; p 0.703), mean KT/V (R² 0.001; p 0.853), and interdialytic weight gain (R² 0.025; p 0.265) on the SUA level. The results showed that none of the included factors had a significant effect on the SUA level. This may indicate that the SUA level in HD patients may be determined by other factors not included in this study, such as dietary habits, concomitant medication therapy, except urate-lowering drugs, genetic factors, etc. Conclusion Further studies are needed to identify factors influencing the SUA level and to determine safe SUA levels in CKD patients on HD.