Replenishing ascorbic acid stores (vitamin C) in patients following hemodialysis (HD) provides no lasting benefits with respect to mineral and bone disorders, according to new findings published in Kidney & Blood Pressure Research.
In a systematic review and meta-analysis of 6 randomized controlled trials including 371 HD patients with chronic kidney disease mineral bone disorders (CKD-MBD), ascorbic acid supplementation (intravenous or dialysate) failed to improve serum phosphorus or parathyroid hormone levels over weeks or months, compared with placebo or standard care. Ascorbic acid (AA) treatment did, however, slightly increase serum calcium in the short term. Researchers determined that included studies had only low to moderate risk for bias.
Some earlier research had suggested that ascorbic acid could reduce phosphorus or delay secondary hyperparathyroidism.
“Our systematic review and meta-analysis does not support prescription of AA to HD patients with CKD-MBD,” Shuangxin Liu, MD, of Affiliated Hospital/Clinical Medical College of Chengdu University and colleagues concluded. They added that clinicians should beware of potential complications from high doses of ascorbic acid, such as hyperoxaluria and oxalate nephropathy. In addition, hypercalcemia may increase risks for cardiovascular events and mortality. In the 6 trials, none of the patients reported adverse side effects from treatment.
Ke G, Huang J, Zhu Y, et al. Effect of ascorbic acid on mineral and bone disorders in hemodialysis patients: a systematic review and meta-analysis. Kidney Blood Press Res 43:1459–1471. DOI:10.1159/000493661