Plasma oxalate levels in prevalent hemodialysis patients and potential implications for ascorbic acid supplementation

Scurvy in a hemodialysis patient. Rare or ignored?

“…Another study found that long‐term intravenous supplemental vitamin C in moderate doses of 250–500 mg weekly led to increase in plasma oxalate levels that exceeded the supersaturation threshold for calcium oxalate in some patients . In a recent study of 197 HD patients, Liu et al found that mean pre‐HD plasma oxalate was 22.3 mmol/L, much lower than the levels of 39–49.8 mmol/L that were seen in older series when patients received less efficient HD . They reported a 71% decrease in mean plasma oxalate during a single, high‐flux dialysis session.…”

“…20 In a recent study of 197 HD patients, Liu et al found that mean pre-HD plasma oxalate was 22.3 mmol/L, much lower than the levels of 39-49.8 mmol/L that were seen in older series Scurvy in hemodialysis patient Hemodialysis International 2018; 22:S83-S87 S85 when patients received less efficient HD. 21 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.…”

“…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 . 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 .…”

“…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. 23 Currently, most commercially available formulations of renal vitamins for dialysis patients contain 60-100 mg of vitamin C. 24 Pharmacokinetics of vitamin C are complex, and the body tightly regulates the tissue and plasma concentrations of vitamin C. Vitamin C has a molecular weight of 176 Daltons, and it is entirely water soluble-not bound to any proteins, hence its substantial clearance by dialysis.…”

Vitamin C-induced oxalate nephropathy in a renal transplant patient related to excessive ingestion of cashew pseudofruit (Anacardium occidentale L.): a case report

“…In renal failure, oxalate excretion decreases roughly in proportion to the decrease in renal function as serum oxalate concentration increases [ 6 , 8 ]. The blood levels of oxalate can achieve supersaturation and precipitate mainly in the kidneys, bones, joints, cardiac conductive system, blood vessels, and retina [ 9 ].…”