Study

Endpoint

Treatment

Results

Azadibakshsh, et al. [94]

Effect of high dose oral folic acid and vitamin B12 on homocysteine levels

High dose oral folic acid (15 mg/day) + vitamin B12 (1 mg/day)

Significant reduction in total homocysteine  levels by 30% with a desirable effect on serum folic acid and vitamin B12 levels

Elian, et al. [95]

Effect of hydroxocobalamin on plasma total homocysteine and methylmalonic acid levels

1 mg hydroxocobalamin subcutaneously per week after hemodialysis

vs .

standard treatment (oral folic acid + pyridoxine + vitamin B12)

32% reduction in plasma total homocysteine and 19% reduction in methylmalonic acid levels

Vrentzos, et al. [97]

Effect of oral vs. intravenous vitamin B12 with oral folic acid on homocysteine levels

Oral folic acid (1 mg/day) + oral vitamin B12 (600 mcg)

vs.

Oral folic acid (1 mg/day) + 1 mg intravenous vitamin B12

Significant reduction in total homocysteine levels with intravenous treatment compared to oral treatment

Chiu, et al. [98]

Effect of intravenous vitamin B12 alone vs. intravenous low-dose folic acid alone vs. combination of both on homocysteine levels

1 mg Intravenous vitamin B12 weekly after hemodialysis

vs.

3mg intravenous folic acid weekly

 vs.

combination of both

Intravenous vitamin B12 alone is as effective as intravenous low-dose folic acid in lowering homocysteine levels with the combination of both having a greater effect

Koyama, et al. [99]

Effect of high dose oral folic acid vs intravenous methylcobalamin vs combination of both on homocysteine levels

High dose oral folic acid (15 mg/day)

vs.

500 mg intravenous methylcobalamin after each hemodialysis

vs.

Combination of both

Similar efficacy of both treatments in reducing homocysteine levels, with greater effect in combination

Kaplan, et al. [100]

Effect of parenteral vitamin B12 alone on homocysteine levels

Three parenteral injections of 1 mg vitamin B12 given at 4-week intervals

Significant reduction in  homocysteine levels and increase in serum B12 levels

Arnadottir, et al. [105]

Effect of oral vitamin B12 on homocysteine levels and vitamin B12 levels

2 mg oral vitamin B12 3 times a week (after each dialysis session) for 6 weeks

vs.

No treatment

Significant increase in serum vitamin B12 levels in treated group with no significant reduction in homocysteine levels compared to control group

Polkinghorne, et al. [88]

Effect of intramuscular  vitamin B12 on homocysteine levels and vitamin B12 levels

1 mg intramuscular vitamin B12 monthly for 3 months

vs.

1 ml saline placebo injection

Significant increase in serum vitamin B12 levels in treated group with no significant reduction in homocysteine levels compared to placebo group

Hoffer, et al. [106]

Comparison of different intravenous cyanocobalamin dosage regimens on plasma homocysteine

1 mg Intravenous cyanocobalamin post-dialysis every 28, 14, and 7 days + routine oral vitamin B

7- or 14-day intervals had a similar effect on reducing homocysteine concentrations, with 7-day regimen increasing serum B12 the most

Hoffer, et al. [107]

Effect of different formulations of vitamin B12 on serum homocysteine and vitamin B12 levels

1 mg intravenous hydroxocobalamin weekly for 8 weeks followed by cyanocobalamin for 8 weeks

vs.

1 mg intravenous cyanocobalamin weekly for 8 weeks followed by hydroxocobalamin for 8 weeks

Hydroxocobalamin increased serum vitamin B12 concentrations 40-fold compared to cyanocobalamin which   increased them only 10-fold, but both treatments reduced plasma homocysteine  concentrations similarly by 33%

Dierks, et al. [108]

Effect of vitamin B12 in patients with low baseline serum levels (< 180 pmol/L) on homocysteine and methylmalonic acid levels

1 mg intravenous cyanocobalamin weekly for 4 weeks

Reduction in plasma total homocysteine and methylmalonic acid levels by 35% and 48%, respectively