Body fluid volume calculated using the uric acid kinetic model relates to the vascular event.

Purpose: We developed a method to measure the extracellular and intracellular fluid volumes using the kinetics of uric acid in the bodies of Japanese patients undergoing dialysis. In this research, we aimed to assess the prognosis of vascular events using this uric acid kinetic model method.

Methods: We conducted a retrospective cohort study of 1,298 patients who were undergoing hemodialysis or predilution online hemodiafiltration at the end of December 2019 at 13 institutions in Japan. Information on vascular events was acquired in 2020. Vascular event prognosis was defined as the new incidence of one or more of the following four types of vascular events: myocardial infarction, cerebral infarction, cerebral hemorrhage, or limb amputation. We measured the extracellular fluid volume and intracellular fluid volume after dialysis using the uric acid kinetic model method and determined the association between ECV, ICV, and vascular event risk.

Results: A high extracellular volume was substantially linked to an increased risk of vascular events. In addition, while a crude analysis revealed that a high intracellular volume was associated with a low risk of vascular events, this was not statistically significant after multifactorial adjustment. This result was partly affected by the low measurement accuracy of the serum urea nitrogen level used for the intracellular volume calculation.

Conclusions: Extracellular volume calculated using the uric acid kinetic model method is a prognostic factor for vascular events in patients undergoing hemodialysis.