Vitamin C plasma level and response to erythropoietin in patients on maintenance haemodialysis.
BACKGROUND
Intravenous vitamin C supplementation to haemodialysis patients might ameliorate responsiveness to recombinant human erythropoietin (rHuEpo). This study was performed to analyse the relation between vitamin C plasma concentration and response to rHuEpo.


METHODS
In a cross-sectional, single-centre observational study including all haemodialysis patients, pre-dialysis plasma vitamin C concentrations were measured by high-performance liquid chromatography and response to rHuEpo (haemoglobin concentration/international units rHuEpo/kg/week) was recorded together with baseline laboratory data.


RESULTS
Univariate analysis yielded a significant correlation between vitamin C plasma levels and response to rHuEpo (n = 130, r = 0.25, P = 0.004), which still persisted after adjustment for transferrin saturation, C-reactive protein, malondialdehyde, parathyroid hormone, route of rHuEpo administration, residual renal function and diabetes mellitus (adjusted r = 0.23, P = 0.014). Analysis per quartiles of vitamin C plasma level revealed a significantly lower response to rHuEpo with decreasing vitamin C values (P = 0.026).


CONCLUSIONS
In unselected haemodialysis patients, vitamin C plasma levels account, at least partially, for the response to rHuEpo. Larger-sized interventional studies are needed to find out whether vitamin C plasma levels may or may not appropriately reflect the potential beneficial effect of vitamin C supplements on rHuEpo responsiveness.
Universitätsklinik für Innere Medizin III, Klinische Abteilung für Nephrologie und Dialyse, Währinger Gürtel 18-20, 1090 Vienna, Austria. robert.deicher@nephro.imed3.akh-wien.ac.at
Robert
R
Deicher
Farzad
F
Ziai
Antje
A
Habicht
Christian
C
Bieglmayer
Martin
M
Schillinger
Walter H
WH
Hörl
D000368:Aged; D000740:Anemia / Q000188:drug therapy* / Q000209:etiology; D001205:Ascorbic Acid / Q000097:blood / Q000502:physiology*; D003430:Cross-Sectional Studies; D004921:Erythropoietin / Q000627:therapeutic use*; D005260:Female; D006397:Hematinics / Q000627:therapeutic use*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins; D006435:Renal Dialysis
D006397:Hematinics; D011994:Recombinant Proteins; D004921:Erythropoietin; D001205:Ascorbic Acid