Ascorbic acid for anemia management in hemodialysis patients: a systematic review and meta-analysis.
BACKGROUND
Ascorbic acid is believed to improve anemia in patients with end-stage renal disease, but its overall effectiveness is unclear.


METHODS
Systematic review and meta-analysis.


METHODS
Adult hemodialysis patients.


METHODS
Randomized clinical trials of ascorbic acid use in addition to standard anemia management.


METHODS
Ascorbic acid.


RESULTS
Weighted mean difference (WMD) for change in hemoglobin level, recombinant human erythropoietin (rHuEPO) dose, transferrin saturation and ferritin level and adverse events.


RESULTS
Of 157 potentially relevant studies, 6 studies (n = 326 patients) met the inclusion criteria. Combining the 3 randomized clinical trials involving patients with baseline hemoglobin levels <11 g/dL, change in hemoglobin level was greater for ascorbic acid use compared with standard care (WMD, 0.9 g/dL; 95% CI, 0.5-1.2 g/dL). Compared with standard care, ascorbic acid use also was associated with a statistically significant decrease in rHuEPO dose (WMD, -17.1 U/kg/wk; 95% CI, -26.0 to -8.2 U/kg/wk) and improvement in transferrin saturation (WMD, 7.9%; 95% CI, 5.2-10.5%), with no change in ferritin concentration. Adverse events had questionable relevance to ascorbic acid use; no study reported oxalate levels or occurrence of oxalosis.


CONCLUSIONS
Small number of studies, heterogeneity between study populations, and study durations were short. Adverse events were poorly reported.


CONCLUSIONS
Although the studies are limited by small numbers of subjects, short durations of follow-up, and variable quality, these results suggest that compared with standard care, ascorbic acid use may result in an increase in hemoglobin concentration and transferrin saturation and decrease in rHuEPO requirements. Longer term studies are required to confirm these results, provide information about adverse events, and determine whether these changes translate into improved patient outcomes and cost-effectiveness.
Department of Medicine, University of Calgary, Calgary, Alberta, Canada.
Vinay
V
Deved
Penelope
P
Poyah
Matthew T
MT
James
Marcello
M
Tonelli
Braden J
BJ
Manns
Michael
M
Walsh
Brenda R
BR
Hemmelgarn
D000328:Adult; D000740:Anemia / Q000097:blood / Q000188:drug therapy*; D001205:Ascorbic Acid / Q000009:adverse effects / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000628:therapy*; D008875:Middle Aged; D006435:Renal Dialysis; D016896:Treatment Outcome
D006454:Hemoglobins; D001205:Ascorbic Acid