Background: Many regimens using different doses of folic acid (FA) alone or with supplementation of B-complex vitamins (BCV) have been tested for the reduction of total homocysteine (tHcy) levels in hemodialysis (HD) patients. BCV are usually administered orally and for a short period. In the present study, we assessed the effect of long-term intravenous (IV) BCV on serum tHCy levels in HD patients, and the effect produced by moderate oral supplementation with FA.
Methods: In a cohort of 37 patients under chronic HD treatment for a mean of 50.2 +/- 46.7 months, serum concentrations of tHcy, folate and vitamin B12 were determined at the end of four sequential periods: (A) three months without any FA supplementation, (B) three months with oral supplementation of 5 mg of FA three times weekly, (C) six months without FA supplementation, and (D) three months without BVC or FA supplementation. From the start of HD treatment and throughout the study until the beginning of period D, patients received a standard IV dose of BCV (B1 250 mg + B6 250 mg + B12 1.5 mg) three times per week, post-dialysis.
Results: At the end of period B, mean serum tHcy levels were significantly lower than in periods A and C (13.7 +/- 3.6 micromol/L vs 19.6 +/- 10.8 micromol/L and 21.3 +/- 9.4 micromol/L, respectively, p < 0.001) and mean serum folate levels were significantly higher (20.7 +/- 7.4 ng/mL vs 5.0 +/- 2.8 ng/mL and 4.5 +/- 1.4 ng/mL, respectively, p < 0.01). At the end of period D, mean serum tHcy levels were significantly higher than in all the previons periods (29.3 +/- 13.5 micromol/L, p < 0.001). Twenty-six of the 37 patients (70.2%) had normal (< 15 micromol/L) serum tHcy levels at the end of period B and only one (2.7%) had normal tHcy at the end of period D. Mean serum vitamin B12 levels at the end of periods A, B and C were 100 times the usual normal values. At the end of period D, although significantly lowered (p < 0.001), they remained above the normal range.
Conclusions: Long-term high-dose BCV IV three times a week post-dialysis reduced serum tHcy levels only when combined with oral FA supplementation.