title: Effect of vitamin C supplementation on serum uric acid in patients undergoing hemodialysis: a randomized controlled trial.
abstract: BACKGROUND
  Clinical studies of recent years have shown that hyperuricemia is associated with poor outcomes such as cardiovascular mortality and dialysis inadequacy in patients undergoing hemodialysis. Our study investigated the effect of vitamin C supplementation on serum uric acid levels in hemodialysis patients.
  
  
  METHODS
  This randomized placebo-controlled trial was conducted on 172 hemodialysis patients. They were randomly divided into the intervention group, to receive 250 mg of vitamin C, three times per week, for 8 weeks, and control groups 1 and 2, to receive placebo injection (saline) and no intervention, respectively. Serum levels of uric acid and creatinine were measured at the start of the study and also after 8 weeks.
  
  
  RESULTS
  The mean of serum levels of uric acid was 6.02 ± 1.08 mg/dL (reference range, 2.6 mg/dL to 6 mg/dL). Nearly, half of the patients (46.7%) had a serum level of uric acid greater than 6 mg/dL. The median baseline serum levels of uric acid were 6.2 mg/dL, 5.9 mg/dL, and 6 mg/dL in the intervention, control 1, and control 2 groups, respectively (P = .19). After 2 months, median levels reduced significantly in the vitamin C group to 5.8 mg/dL as compared to 6.4 mg/dL and 6.3 mg/dL in control groups (P = .02). The mean serum creatinine level had no significant changes during the study.
  
  
  CONCLUSIONS
  Our results demonstrated the existence of a significant negative relationship between vitamin C and serum uric acid levels. Detailed investigations with larger sample sizes and longer-term use of vitamin C are recommended.
authors.affiliation: Drug Applied Research Center Tabriz University of Medical Sciences, Tabriz; Division of Nephrology, Shahid Beheshti University of Medical Sciences, Tehran, Iran. parvin1351@yahoo.com.
authors.forename: Vajihe
authors.initials: V
authors.lastname: Biniaz
authors.forename: Ali
authors.initials: A
authors.lastname: Tayebi
authors.forename: Abbas
authors.initials: A
authors.lastname: Ebadi
authors.forename: Mehdi
authors.initials: M
authors.lastname: Sadeghi Shermeh
authors.forename: Behzad
authors.initials: B
authors.lastname: Einollahi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001205:Ascorbic Acid / Q000627:therapeutic use*; D003404:Creatinine / Q000097:blood; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D033461:Hyperuricemia / Q000517:prevention & control*; D007676:Kidney Failure, Chronic / Q000628:therapy; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D016896:Treatment Outcome; D014527:Uric Acid / Q000097:blood*; D014815:Vitamins / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D014815:Vitamins; D014527:Uric Acid; D003404:Creatinine; D001205:Ascorbic Acid