Plasma oxalate levels in prevalent hemodialysis patients and potential implications for ascorbic acid supplementation.
OBJECTIVE
Ascorbic acid (AA) supplementation may increase hemoglobin levels and decrease erythropoiesis-stimulating agent dose requirement in patients with end stage renal disease (ESRD). While plasma AA levels >100μM may be supratherapeutic, levels of at least 30μM may be needed to improve wound healing and levels may need to reach 70μM to optimize erythropoiesis. Of concern, oxalate (Ox), an AA metabolite, can accumulate in ESRD. Historically, if plasma Ox levels remain ≥30μM, oxalosis was of concern. Contemporary hemodialysis (HD) efficiencies may decrease the risk of oxalosis by maintaining pre-HD Ox levels <30μM. This study focuses on the plasma Ox levels in HD patients.


METHODS
A prospective, observational study of 197 HD patients with pre-HD AA levels and pre-HD and post-HD Ox levels.


RESULTS
Mean plasma Ox levels decreased 71% during the intradialytic period (22.3±11.1μM to 6.4±3.2μM, P<0.001). In regression analysis, pre-HD plasma AA levels ≤100μM were not associated with a pre-HD plasma Ox level≥30μM, even if ferritin levels were increased. Pre-HD plasma Ox levels ≥20 or ≥30μM were not associated with lower cumulative 4-year survival.


CONCLUSIONS
Pre-HD plasma AA levels up to 100μM in HD patients do not appear to be associated with an increased risk of developing secondary oxalosis, as the corresponding pre-HD plasma Ox level appears to be maintained at tolerable levels.
University of Massachusetts, Lowell 3 Solomont Way, Lowell, MA 01854, United States.
Yuguan
Y
Liu
Cooper Medical School of Rowan University 401 Haddon Avenue, Camden, NJ 08103, United States.
Lawrence S
LS
Weisberg
Northwestern University School of Medicine 225 East Chicago Avenue, Chicago, IL, 60611, United States.
Craig B
CB
Langman
Cooper University Hospital Research Institute 401 Haddon Avenue, Camden, NJ 08103, United States.
Amanda
A
Logan
Biostatistics, Cooper University Hospital Research Institute 401 Haddon Avenue, Camden, NJ 08103, United States.
Krystal
K
Hunter
Department of Medicine, Cooper University Hospital 401 Haddon Avenue, Camden, NJ 08103, United States.
Deepali
D
Prasad
Department of Medicine, Cooper University Hospital 401 Haddon Avenue, Camden, NJ 08103, United States.
Jose
J
Avila
Department of Medicine, Cooper University Hospital 401 Haddon Avenue, Camden, NJ 08103, United States.
Thaliga
T
Venkatchalam
University of Pennsylvania School of Medicine 3400 Civic Center Blvd, Philadelphia, PA 19104, United States.
Jeffrey S
JS
Berns
University of Massachusetts, Lowell 3 Solomont Way, Lowell, MA 01854, United States.
Garry J
GJ
Handelman
Cooper Medical School of Rowan University 401 Haddon Avenue, Camden, NJ 08103, United States. Electronic address: Sirover-William@cooperhealth.edu.
William D
WD
Sirover
D000368:Aged; D001205:Ascorbic Acid / Q000008:administration & dosage*; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010070:Oxalates / Q000097:blood*; D011446:Prospective Studies; D006435:Renal Dialysis
D006454:Hemoglobins; D010070:Oxalates; D001205:Ascorbic Acid
Ascorbic acid; Hemodialysis; Nutrition; Oxalate