Hemoglobin and plasma vitamin C levels in patients on peritoneal dialysis.
OBJECTIVE
To determine the contribution of vitamin C (Vit C) status in relation to hemoglobin (Hb) levels in patients on long-term peritoneal dialysis (PD).


METHODS
56 stable PD patients were evaluated in a cross-sectional survey. Plasma samples were collected for Vit C (analyzed by HPLC with electrochemical detection) and high-sensitivity C-reactive protein (hs-CRP) determinations. Clinical records were reviewed for Hb, transferrin saturation (TSAT), ferritin, erythropoietin (EPO) dose, and other clinical parameters. Dietary Vit C intake was evaluated by patient survey and from patient records. Total Vit C removed during PD treatment was measured in 24-hour dialysate collections.


RESULTS
Patients showed a highly skewed distribution of plasma Vit C levels, with 40% of patients below normal plasma Vit C levels (<30 μmol/L) and 9% at higher than normal levels (>80 μmol/L). Higher plasma Vit C levels were associated with higher Hb levels (Pearson r = 0.33, p < 0.004). No direct connection between Vit C levels and reported dietary intake could be established. In stepwise multiple regression, plasma Vit C remained significantly associated with Hb (p = 0.017) but there was no significant association with other variables (dialysis vintage, age, ferritin, TSAT, hs-CRP, residual renal function, and EPO dose). In 9 patients that were evaluated for Vit C in dialysate, plasma Vit C was positively associated (Spearman r = 0.85, p = 0.01) with the amount of Vit C removed during dialysis treatment.


CONCLUSIONS
These data indicate that plasma Vit C is positively associated with higher Hb level. Vit C status could play a major role in helping PD patients to utilize iron for erythropoiesis and achieve a better Hb response during anemia management.
Finkelstein
Fredric O
FO
New Haven CAPD, New Haven, Connecticut, USA.
Juergensen
Peter
P
Wang
Suxin
S
Santacroce
Sally
S
Levine
Mark
M
Kotanko
Peter
P
Levin
Nathan W
NW
Handelman
Garry J
GJ
D001205:Ascorbic Acid / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis
D006454:Hemoglobins; D001205:Ascorbic Acid