Randomized, crossover study of the effect of vitamin C on EPO response in hemodialysis patients.
BACKGROUND
Vitamin C has been reported to be an effective adjuvant agent in the treatment of anemia in iron-overloaded hemodialysis patients. We aim to evaluate its effect on erythropoietin (EPO) response in a prospective, randomized, double-blind, crossover study.


METHODS
Sixty-three patients were randomly divided into two groups. Group 1 was treated with intravenous vitamin C, 500 mg, three times a week, and group 2, with placebo for 6 months. During the second 6-month period, group 1 was treated with placebo, and group 2, with the same dose of vitamin C. Thirty patients in group 1 and 28 patients in group 2 completed the study. Hemoglobin levels, weekly EPO dose, and ratio of EPO to hemoglobin as an index of EPO need were determined at both baseline and the end of the two periods, together with other parameters known to be associated with EPO response.


RESULTS
Twenty patients in group 1 (66.7%) and 18 patients in group 2 (64.3%) were responsive to vitamin C. In both groups, vitamin C resulted in a significant increase in hemoglobin levels (P < 0.0001 for both) and a significant decrease in EPO-hemoglobin ratio (P < 0.0001, P = 0.019). Transferrin saturation also increased with vitamin C treatment in both groups (P = 0.009, P = 0.005). All these parameters remained stable with placebo in both groups. Other parameters did not change throughout the study.


CONCLUSIONS
Vitamin C can be used as an effective adjuvant therapy to EPO in hemodialysis patients. Further studies are needed to determine possible predictors of hematologic response to vitamin C.
Keven
Kenan
K
Department of Nephrology, Ankara University Medical School, Ankara, Turkey.
Kutlay
Sim
S
Nergizoglu
Gökhan
G
Ertürk
Sehsuvar
S
D000328:Adult; D000740:Anemia / Q000188:drug therapy* / Q000209:etiology; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004347:Drug Interactions; D004921:Erythropoietin / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007275:Injections, Intravenous; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis; D014168:Transferrin / Q000032:analysis; D016896:Treatment Outcome
D006454:Hemoglobins; D014168:Transferrin; D004921:Erythropoietin; D001205:Ascorbic Acid