Different doses of oral folic acid for homocysteine-lowering therapy in patients on hemodialysis: a randomized controlled trial.

INTRODUCTION: We compared the effect of higher and lower doses of folic acid compared to our routine daily dose on plasma homocysteine levels, in our hemodialysis patients. MATERIALS AND METHODS: Eighty patients on hemodialysis receiving oral folic acid, 10 mg/d, were randomized to receive folic acid at either doses of 5 mg/d (group 1) or 15 mg/d (group 2) for 2 months. Plasma levels of total homocysteine were measured before and after the study period. RESULTS: Hyperhomocysteinemia was seen in 75 patients (93.8%) before, and in 37 patients of group 1 (92.5%) and 39 of group 2 (97.5%) after the study period. In group 1, a nonsignificant decrease occurred in plasma homocysteine level (29.67 +/- 12.26 micromol/L to 27.78 +/- 9.94 micromol/L, P = .30), while in group 2, there was a significant decrease in homocysteine level (32.40 +/- 9.76 micromol/L to 29.58 +/- 9.62 micromol/L, P = .01). Changes in homocysteine level correlated with its baseline level (r = -0.42, P < .001). In both groups, significant reductions in homocysteine level were seen mostly in those patients with high baseline homocysteines. CONCLUSIONS: Routine folic acid supplementation of 10 mg/d could not normalize plasma homocysteine levels in most of our patients. Increasing folic acid dose made a statistically significant but clinically trivial decrease in homocysteine levels, and could not normalize homocysteine level in most patients. Patients with a higher baseline homocysteine level achieved a greater reduction, which may be explained by primary noncompliance of some patient. Further investigation of folic acid dosage is suggested.