title: Plasma ascorbic acid concentrations in prevalent patients with end-stage renal disease on hemodialysis.
abstract: OBJECTIVE
  To determine the prevalence of vitamin C (ascorbic acid [AA]) deficiency in patients with end-stage renal disease, the effect of supplemental AA on plasma AA concentrations, and the extrinsic and intrinsic factors that affect plasma AA concentrations in this patient population.
  
  
  METHODS
  In study 1, we compared the effect of hemodialysis (HD) on plasma AA concentrations between patients with low and high pre-HD AA concentrations. In study 2, we analyzed kinetic and nonkinetic factors for their association with increased plasma AA concentrations in patients on maintenance HD. Study 1 was performed in a single outpatient HD clinic in Cherry Hill, New Jersey. Study 2 was performed in 4 outpatient HD clinics in Southern New Jersey.
  
  
  METHODS
  In study 1, we collected plasma samples from 8 adult patients on maintenance HD at various time points around their HD treatment and assayed them for AA concentration. In study 2, we enrolled 203 adult patients and measured pre-HD plasma AA concentrations. We ascertained supplemental AA use and assessed dietary AA intake.
  
  
  METHODS
  In study 1, plasma AA concentrations were compared during the intradialytic and interdialytic period. In study 2, pre-HD plasma AA concentrations were correlated with supplement use and demographic factors.
  
  
  RESULTS
  Study 1 showed that over the course of a single HD treatment, the plasma AA concentration decreased by a mean (±standard deviation) of 60% (±6.6). In study 2, the median pre-HD plasma AA concentration was 15.7 μM (interquartile range, 8.7-66.8) in patients who did not take a supplement and 50.6 μM (interquartile range, 25.1-88.8) in patients who did take a supplement (P < .001). Supplement use, increasing age, and diabetes mellitus were associated with a pre-HD plasma AA concentration ≥30 μM.
  
  
  CONCLUSIONS
  HD depletes plasma AA concentrations, and AA supplementation allows patients to achieve higher plasma AA concentrations.
authors.affiliation: Division of Nephrology, Department of Medicine, Cooper Medical School of Rowan University, Camden, New Jersey. Electronic address: sirover-william@cooperhealth.edu.
authors.forename: William D
authors.initials: WD
authors.lastname: Sirover
authors.affiliation: Clinical Laboratory and Nutritional Sciences, University of Massachusetts, Lowell, Massachusetts.
authors.forename: Yuguan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Cooper Research Institute, Camden, New Jersey.
authors.forename: Amanda
authors.initials: A
authors.lastname: Logan
authors.affiliation: Department of Biostatistics, Cooper Research Institute, Camden, New Jersey.
authors.forename: Krystal
authors.initials: K
authors.lastname: Hunter
authors.affiliation: Lankenau Medical Center and Lankenau Institute for Medical Research, Wynnewood, Pennsylvania.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Benz
authors.affiliation: Department of Medicine, Cooper University Hospital, Camden, New Jersey.
authors.forename: Deepali
authors.initials: D
authors.lastname: Prasad
authors.affiliation: Department of Medicine, Cooper University Hospital, Camden, New Jersey.
authors.forename: Jose
authors.initials: J
authors.lastname: Avila
authors.affiliation: Department of Medicine, Cooper University Hospital, Camden, New Jersey.
authors.forename: Thaliga
authors.initials: T
authors.lastname: Venkatchalam
authors.affiliation: Division of Nephrology, Department of Medicine, Cooper Medical School of Rowan University, Camden, New Jersey.
authors.forename: Lawrence S
authors.initials: LS
authors.lastname: Weisberg
authors.affiliation: Clinical Laboratory and Nutritional Sciences, University of Massachusetts, Lowell, Massachusetts.
authors.forename: Garry J
authors.initials: GJ
authors.lastname: Handelman
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000097:blood*; D001206:Ascorbic Acid Deficiency / Q000150:complications / Q000453:epidemiology*; D048909:Diabetes Complications; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000150:complications / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis
chemical_list: D001205:Ascorbic Acid