Background: Low plasma ascorbate levels in hemodialysis patients have been reported worldwide; hence, many end-stage kidney disease patients are forced to restrict their diets, especially potassium-rich fruits and vegetables, to prevent hyperkalemia. In this study, we aimed to clarify whether plasma ascorbate levels are low in Japanese dialysis patients and whether plasma ascorbate levels fluctuate before and after dialysis. In addition, we aimed to clarify whether there are clinical test items that have a causal relationship with plasma ascorbate levels.
Methods: Plasma ascorbate levels in 27 chronic kidney disease (CKD) stage G3–G5 patients (mean age 84 years) and pre- and post-dialysis plasma ascorbate levels in 19 CKD stage G5D hemodialysis patients (mean age 79 years) were determined using high-performance liquid chromatography and electrochemical detection.
Results: Pre-dialysis plasma ascorbate levels in hemodialysis patients (12.0 ± 1.4 µM) were significantly lower (by 56%) than those in CKD stage G3–G5 patients (27.1 ± 2.7 µM). After dialysis, there was a 40% reduction in plasma ascorbate levels. Moreover, pre-dialysis ascorbate levels correlated significantly with plasma potassium levels.
Conclusions: The study results indicate that Japanese hemodialysis patients have lower plasma ascorbate levels than CKD stage G3–G5 patients and that these low plasma ascorbate levels in hemodialysis patients were further reduced by hemodialysis. To avoid the development of scurvy in hemodialysis patients, it is necessary to take sufficient ascorbate from supplements or medicines.