Treatment of hyperhomocysteinemia in renal transplant recipients. A randomized, placebo-controlled trial
Background: Stable renal transplant recipients have an excess prevalence of hyperhomocysteinemia, which is a risk factor for arteriosclerosis. Objective: To determine the effect of treatment with 1) vitamin B6 or 2) folic acid plus vitamin B12 on fasting and post-methionine-loading plasma total homocysteine levels in renal transplant recipients. Design: Block- randomized, placebo-controlled, 2 x 2 factorial study. Setting: University- affiliated transplantation program. Patients: 29 clinically stable renal transplant recipients. Intervention: Patients were randomly assigned to one of four regimens: placebo (n = 8); vitamin B6, 50 mg/d (n = 7); folio acid, 5 mg/d, and vitamin B12, 0.4 mg/d (n = 7); or vitamin B6, 50 mg/d, folic acid, 5 mg/d, and vitamin B12, 0.4 mg/d (n = 7). Measurements: Fasting and 2-hour post-methionine loading plasma total homocysteine levels. Results: Vitamin B6 treatment resulted in a 22.1% reduction in geometric-mean post- methionine-loading increases in plasma total homocysteine levels (P = 0.042), and folio acid plus vitamin B12 treatment caused a 26.2% reduction in geometric-mean fasting plasma total homocysteine levels (P = 0.027). These results occurred after adjustment for age; sex; and pretreatment levels of total homocysteine, B vitamins, and creatinine. Conclusions: Vitamin B6 should be added to the combination of folic acid and vitamin B12 for effective reduction of both post-methionine-loading and fasting plasma total homocysteine levels in renal transplant recipients.