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.

Comparison of Body Fluid Volumes Determined by Kinetic Modeling and by Bioimpedance Spectroscopy.

INTRODUCTION: The bioimpedance spectroscopy (BIS) method is used in individual patients requiring body fluid volume measurement. In a hemodialysis facility, however, regular screening of body fluid volumes is also necessary. Such screening, by kinetic modeling, may become possible by calculating distribution volumes of urea and uric acid from regular blood test results. OBJECTIVE: The aim is to compare uric acid distribution volumes with BIS-extracellular volume, urea distribution volume with BIS-total body water, and difference between urea and uric acid distribution volumes with BIS-intracellular volume. METHODS: We reanalyzed stored blood test data of 53 hemodialysis patients obtained together with BIS data of the same patients in our previous study. RESULTS: Significant correlations were found between urea distribution volume and total body water predicted by the BIS method, between uric acid distribution volume and extracellular volume predicted by the BIS method, and between the difference of uric acid distribution volume from urea distribution volume and intracellular volume predicted by the BIS method. In Bland-Altman analysis, comparison of each pair showed no systematic error. The mean difference between each pair was minimal. CONCLUSION: Fluid volumes in different body compartments can be estimated by kinetic modeling as well as by the BIS method.

Recent analysis of status and outcomes of peritoneal dialysis in the Tokai area of Japan: the second report of the Tokai peritoneal dialysis registry.

BACKGROUND: Early withdrawal within 3 years after starting peritoneal dialysis (PD) and PD-related peritonitis have been major obstacles preventing increases in the population of PD patients. To address these problems, we implemented education programs for medical staff. This study analyzed the recent status and outcomes of PD therapy, focusing on findings such as the incidence and prognosis of peritonitis as of 5 years after our last study. METHODS: We investigated background, laboratory data and status of PD therapy, reasons for withdrawal from PD and incidental statements on peritonitis from 2010 to 2012 (R2), and compared findings with those from our last study of 2005-2007 (R1). RESULTS: Early PD therapy withdrawal in R2 clearly improved to 44.7 %, compared with 50.9 % in R1. Peritonitis incidence improved slightly from once per 42.8 months/patient in R1 to once per 47.3 months/patient in R2. Notably, PD-related peritonitis as a cause of mortality improved markedly in R2, but outcomes of PD-related peritonitis did not change significantly between R1 and R2. In contrast, social problems increased as a reason for withdrawal from PD therapy. CONCLUSION: Our efforts at education might have been useful for improving early withdrawal from PD and deaths attributable to PD-related peritonitis. However, since improvements to incidence of PD-related peritonitis were limited by education, further improvement in PD-related peritonitis incidence requires development of new sterilized connecting systems during PD-bag exchanges to decrease PD-related peritonitis opportunities. Construction of medical support systems to address social problems is required to maintain long-term PD therapy.

Peritonitis is still an important factor for withdrawal from peritoneal dialysis therapy in the Tokai area of Japan.

BACKGROUND: In Japan, the population of patients on peritoneal dialysis (PD) is <4% of the total number of patients with end-stage renal disease. Few systemic analyses have examined why the number of PD patients has not increased in Japan. We organized a registry to analyze PD patients and retrospectively investigated 561 PD patients (about 5% of all Japanese PD patients) from 13 hospitals in the Tokai area for 3 years from 2005. METHODS: We investigated background, physical status, laboratory data, status of PD therapy, and the occurrence of PD-related complications, and analyzed reasons for withdrawal from PD. RESULTS: Nutrition did not change significantly during our observation. Urinary volume showed continued decreases after the introduction period. In contrast, PD fluid demand and ultrafiltration volume were significantly increased. For calcium metabolism, multiple phosphate binders were required after the second year of PD therapy. Early drop-out within 3 years after starting PD therapy comprised 50.9% of total withdrawals, with PD-related peritonitis as the most common reason, mainly caused by Gram-positive organisms. Incidence of peritonitis was 42.8 months/patient. Culture-negative results were obtained for 32% of peritonitis cultures. Diabetes affects the prognosis of PD therapy, but not the incidence of peritonitis. CONCLUSION: We examined clinical status over 3 years in the Tokai area. The results suggest that the incidence of peritonitis needs to be decreased to prevent early withdrawal of PD patients. Education systems to decrease the incidence of peritonitis and techniques to decrease culture-negative results might be important for improving the prognosis of peritonitis.

Uric acid distribution volume calculated by kinetic modeling and extracellular volume predicted by bioimpedance method.

BACKGROUND: Several reports indicate that extracellular volume predicted by bioimpedance analysis method is associated with hydration status of hemodialysis patients. THEORY: Fundamentally, uric acid does not cross cell membranes by simple diffusion, either by facilitated diffusion or by active transport. In addition, uric acid cannot move through cell membranes in most tissues other than those involved in uric acid excretion. These facts support the interpretation that uric acid distribution volume would therefore correlate with extracellular volume. METHODS: We examined correlation between uric acid distribution volume calculated by uric acid mass-balance modeling from regular blood test results and extracellular volume predicted by bioimpedance analysis predicted by BCM (Fresenius Medical Care) in 53 patients. RESULTS: There was a significant correlation between uric acid distribution volume (x) and extracellular volume predicted by bioimpedance analysis (y): y = 0.69x + 3.39, r2 = 0.61, p < 0.0001. Bland-Altman analysis showed systematic error for uric acid distribution volume versus extracellular volume predicted by bioimpedance analysis (mean difference between uric acid distribution volume and extracellular volume predicted by bioimpedance analysis was 0.94 L, 95% confidence interval of difference was -3.29 to 5.17 L). CONCLUSION: Uric acid distribution volume calculated by uric acid mass-balance modeling from regular blood test results may be an alternative marker of extracellular volume predicted by bioimpedance analysis.