HIGH-DOSE VITAMIN-B TREATMENT OF HYPERHOMOCYSTEINEMIA IN DIALYSIS PATIENTS

Hyperhomocysteinemia, an arteriosclerotic risk factor, persists in 75% of dialysis patients despite routine low dose supplementation with th e B-vitamin co-factors/substrates for homocysteine (Hcy) metabolism, a nd normal or supernormal plasma status of these vitamins (Atherosclero sis 114:93, 1995). We conducted a placebo-controlled eight-week trial of the effect on plasma homocysteine of adding supraphysiologic dose f olic acid (15 mg/day), B-6 (100 mg/day), and B-12 (1 mg/day) to the us ual daily dosing of 1 mg folic acid, 10 mg Ed, and 12 mu g B-12, in 27 hyperhomocysteinemic dialysis patients. Total plasma homocysteine was measured at baseline, and after four and eight weeks. Blinded analyse s revealed no evidence of toxicity in the group randomized to supraphy siologic dose B-vitamin supplementation. Plasma homocysteine was signi ficantly reduced after both four weeks (-29.8% vs. -2.0%; P = 0.0024) and eight weeks (-25.8% vs. +0.6%; P = 0.0009) of active versus placeb o treatment. Also, 5 of 15 treated versus 0 of 12 placebo group patien ts had their plasma Hey reduced to within the normative range (< 15 mu mol/liter). Supraphysiologic doses of B-vitamins may be required to c orrect hyper homocysteinemia in dialysis patients.