Impact of Regular or Extended Hemodialysis and Hemodialfiltration on Plasma Oxalate Concentrations in Patients With End-Stage Renal Disease

Abstract

IntroductionCalcium oxalate supersaturation is regularly exceeded in the plasma of patients with end-stage renal disease (ESRD). Previous reports have indicated that hemodialfiltration (HDF) lowers elevated plasma oxalate (POx) concentrations more effectively compared with hemodialysis (HD). We reevaluate the therapeutic strategy for optimized POx reduction with advanced dialysis equipment and provide data on the effect of extended treatment time on dialytic oxalate kinetics.MethodsFourteen patients with ESRD who underwent HDF 3 times a week for 4 to 4.5 hours (regular HDF; n = 8) or 7 to 7.5 hours (extended HDF; n = 6) were changed to HD for 2 weeks and then back to HDF for another 2 weeks. POx was measured at baseline, pre-, mid-, and postdialysis, and 2 hours after completion of the treatment session.ResultsBaseline POx for all patients averaged 28.0 ± 7.0 μmol/l. Intradialytic POx reduction was approximately 90% and was not significantly different between groups or treatment modes [F(1) = 0.63; P = 0.44]. Mean postdialysis POx concentrations were 3.3 ± 1.8 μmol/l. A rebound of 2.1 ± 1.9 μmol/l was observed within 2 hours after dialysis. After receiving 2 weeks of the respective treatment, predialysis POx concentrations on HD did not differ significantly from those on HDF [F(1) = 0.21; P = 0.66]. Extended treatment time did not provide any added benefit [F(1) = 0.76; P = 0.40].DiscussionIn contrast to earlier observations, our data did not support a benefit of HDF over HD for POx reduction. With new technologies evolving, our results emphasized the need to carefully reevaluate and update traditional therapeutic regimens for optimized uremic toxin removal, including those used for oxalate.

Scurvy in a hemodialysis patient. Rare or ignored?

“…They reported a 71% decrease in mean plasma oxalate during a single, high‐flux dialysis session. In 2017, Ermer et al reported 90% intradialytic reduction in plasma oxalate levels, with no significant differences between standard hemodialfiltration, extended hemodialfiltration, and HD . It has been postulated that if calcium oxalate precipitates are formed during the interdialytic period, such precipitates may dissolve post‐HD and oxalosis does not ensue, as long as the post‐HD plasma oxalate is <30 mmol/L .…”

“…In 2017, Ermer et al reported 90% intradialytic reduction in plasma oxalate levels, with no significant differences between standard hemodialfiltration, extended hemodialfiltration, and HD. 22 It has been postulated that if calcium oxalate precipitates are formed during the interdialytic period, such precipitates may dissolve post-HD and oxalosis does not ensue, as long as the post-HD plasma oxalate is <30 mmol/L. 21 Majority of documented reports of oxalate deposition are from patients who self-medicated large doses of vitamin C (1-2 g per day) and were on older forms of dialysis.…”

Assessment of Plasma Oxalate Concentration in Patients With CKD

“…Usage of a 96-well plate for measurement of oxalate oxidase activity led to lower values for intra-and interassay variability than previously described. 19 The mean coefficient of variation (CV) was 2% for within-run variation and 4%…”

“…The lower limit of detection was determined at 2 mM and validated by the accuracy of both ion chromatography and the oxalate oxidase assay. 19 All measurements less than 2 mM were set to 1.9 mM.…”

Metabolism oxalic acid: failure causes and consequences of molecular-biochemical factors for the formation of oxalate-induced diseases

“…При порушенні гомеостазу оксалатів відбувається їх накопичення у тканинах організму [35]. Відображення цього процесу фіксується підвищенням концентрації оксалатів у плазмі крові та сечі [36]. Порушення обміну ЩК та збільшення її продукції в крові та сечі поділяються на первинні (генетично зумовлені) та вторинні.…”