Serum Urate Levels of Hemodialyzed Renal Patients Revisited

Abstract

Objectives: The need of maintaining serum urate (SU)-lowering agents in hemodialysis (HD) patients is an understudied area that requires a review, as it is a common practice. The aims were to assess the SU reduction achieved under HD and to analyze the kinetics of SU in a week of intermittent HD.

Methods: The serum urate levels were determined before and after HD sessions in 96 consecutive patients with end-stage renal disease, and the average SU reduction was assessed. Variables related to HD were analyzed whether they were associated with SU reductions of 80% greater. In addition, a kinetics study was performed on 10 selected patients with hyperuricemia (SU before HD >6.8 mg/dL) throughout intermittent HD sessions in a 1-week period.

Results: The mean ± SD age of the patients was 66.5 ± 13.8 years, and 62 of them were male (64.6%). The mean ± SD time on HD replacement was 7.1 ± 7.2 years, and 16 (16.4%) continued with urate-lowering agents. The mean SU reduction immediately after HD was 80.2% (95% confidence interval, 78.4-82.0); 51 patients (56.7%) showed SU reduction of 80% or greater. In the SU kinetics study, SU levels significantly reduced all over the period and persisted below hyperuricemia threshold (p = 0.015). Noteworthy, 6 patients (60%) were hyperuricemic before session 1, but only 1 (10%) before session 2 and none before session 3.

Conclusions: Under HD replacement therapy, the SU levels effectively reduced and persisted below saturation point, suggesting that the SU-lowering therapy would be unnecessary for patients on HD, but necessary in selected cases. The definition of hyperuricemia under HD needs to be revised.