Rapid communication: L-folinic acid versus folic acid for the treatment of hyperhomocysteinemia in hemodialysis patients.
BACKGROUND
The hyperhomocysteinemia found in most hemodialysis patients is refractory to combined oral B-vitamin supplementation featuring supraphysiological doses of folic acid (FA). We evaluated whether a high-dose L-folinic acid-based regimen provided improved total homocysteine (tHcy)-lowering efficacy in chronic hemodialysis patients, as suggested by a recent uncontrolled report.


METHODS
We block-randomized 48 chronic, stable hemodialysis patients based on their screening predialysis tHcy levels, sex, and dialysis center into two groups of 24 subjects treated for 12 weeks with oral FA at 15 mg/day or an equimolar amount (20 mg/day) of oral L-folinic acid (FNA) [L-5-formyltetrahydrofolate]. All 48 subjects also received 50 mg/day of oral vitamin B6 and 1.0 mg/day of oral vitamin B12.


RESULTS
The mean percentage (%) reductions (with 95% CIs) in predialysis tHcy were not significantly different [FNA = 22.1% (11.8 to 31.4%), FA = 20.7% (11.7 to 30.5%), P = 0.950 by paired t test]. Final on-treatment values (mean with 95% CI) were as follows: FNA, 15.9 micromol/L (14.0 to 18.0); FA, 16.9 micromol/L (14.8 to 18.8). Moreover, in those subjects with baseline tHcy levels >/=14 micromol/L, neither treatment resulted in "normalization" of tHcy levels (that is, final on-treatment values <12 micromol/L) among a significantly different or clinically meaningful number of patients [FNA = 2 out of 22 (9.1%); FA = 2 out of 24 (8.3%); Fisher's exact test of between groups difference, P = 1.000].


CONCLUSIONS
Relative to high-dose FA, high-dose oral L-folinic acid-based supplementation does not afford improved tHcy-lowering efficacy in hemodialysis patients. The preponderance of hemodialysis patients (that is,> 90%) exhibits mild hyperhomocysteinemia refractory to treatment with either regimen.
Yango
A
A
Division of Renal Diseases, Rhode Island Hospital, Providence, Rhode Island, USA.
Shemin
D
D
Hsu
N
N
Jacques
P F
PF
Dworkin
L
L
Selhub
J
J
Bostom
A G
AG
D000368:Aged; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use*; D006710:Homocysteine / Q000097:blood; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000188:drug therapy* / Q000209:etiology*; D002955:Leucovorin / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis / Q000009:adverse effects*; D016896:Treatment Outcome
D006710:Homocysteine; D005492:Folic Acid; D002955:Leucovorin