Effect of Ascorbic Acid on Mineral and Bone Disorders in Hemodialysis Patients: a Systematic Review and Meta-Analysis

Abstract

Background/Aims: Hemodialysis (HD) patients often have inadequate nutrition, especially with respect to ascorbic acid (AA). It is reported that every HD session may cause a 50%– 75% decrease in plasma AA levels. Some studies have shown that supplementation of AA can change the outcome of chronic kidney disease-mineral bone disorders (CKD-MBD), but the effect of AA on HD patients with CKD-MBD remains controversial. Consequently, we decided to perform a meta-analysis to evaluate the efficacy of AA supplementation in CKD-MBD patients requiring dialysis. Methods: A search was conducted using Pubmed, EMBASE, Cochrane Central Register of Controlled Trials, Chinese National Knowledge Infrastructure (CNKI), Wanfang database and VIP information database up to April 2018 for all English and Chinese language publications. The main indicators of our study were changes in serum phosphate (P), calcium (Ca) and parathyroid hormone (PTH) levels after AA treatment. The efficacy of AA was evaluated by weighted mean difference (WMD) and confidence intervals (CI). Cardiovascular events, mortality and adverse events reported during the experiment were also noted. Results: In total, 371 patients in six studies were involved in this meta-analysis. Compared to placebo, AA treatment had no positive effect on serum P (353 patients; WMD = -0.05; 95% CI, -0.3 to 0.2; I² = 28%) or PTH levels (275 patients; WMD = -17.04; 95%CI, -63.79 to 29.72; I² = 75%). The pooled mean difference of the change of Ca levels from baseline was higher in the AA therapy group versus placebo (353 patients; WMD = 0.15; 95% CI, 0.01 to 0.3; I² = 0%). No side effects were observed. Conclusion: Our systematic review and meta-analysis does not support prescription of AA to HD patients with CKD-MBD. AA had no positive effect on CKD-MBD patients as it couldn’t influence the serum P or PTH levels but did raise serum Ca levels in the short-term.

Reduced Plasma Ascorbate and Increased Proportion of Dehydroascorbic Acid Levels in Patients Undergoing Hemodialysis

“…Therefore, it is important to control the plasma calcium, phosphate, and parathyroid hormone levels in non-hemodialysis CKD and hemodialysis patients [42]. Through a systematic review and meta-analysis, Ke et al [43] reported that vitamin C supplementation in CKD patients had no positive effect that influenced the plasma phosphate or parathyroid hormone levels, but it increased plasma calcium levels in the short term. In the present study, we did not detect any correlation between plasma ascorbate and plasma calcium, phosphate, and parathyroid hormone levels in hemodialysis patients.…”

Evaluating extremely low plasma ascorbate levels and reduction of plasma ascorbate levels by dialysis in Japanese hemodialysis patients

“…Therefore, it is important to control the plasma calcium, phosphate, and parathyroid hormone levels in the non-hemodialysis CKD and hemodialysis patients [41]. Through a systematic review and meta-analysis, Ke et al [42] have reported that vitamin C supplementation in CKD patients has no positive effect that influence the plasma phosphate or parathyroid hormone levels, but it increase plasma calcium levels in the short term.…”

Bone Quality in Chronic Kidney Disease Patients: Current Concepts and Future Directions – Part II

“…Ascorbic acid supplements transiently increased serum calcium level, without significantly affecting serum phosphate and PTH levels. Its use in CKD patients is not supported [ 35 ].…”