Response of hyperhomocysteinemia to folic acid supplementation in patientswith end-stage renal disease

Back round: Elevated concentrations of homocysteine are associated with an increased risk for cardiovascular disease. Reasons for elevated homocystein e concentrations are folate or vitamin B-12 deficiency, renal disease or,ge netic abnormalities. A high prevalence of hyperhomocysteinemia is found in patients with end-stage renal disease (ESRD). Since these patients are also at increased risk for vitamin deficiency, a supplementation study comparin g two doses of folic acid was performed in patients with ESRD treated with maintenance hemodialysis or with peritoneal dialysis. Patients and methods Patients undergoing hemodialysis (n = 70) or peritoneal dialysis (n = 12) w ere supplemented with 2.5 mg or 5 mg folic acid (three times per week after each dialysis treatment) for four weeks in a parallel study design. In 20 hemodialysis patients, the effect of folic acid withdrawal was observed aft er four weeks. Results: Both supplementation schemes reduced homocysteine t o a similar extent (35%) but did not normalize homocysteine concentrations in the majority of patients. Dialysis also had a strong homocysteine loweri ng effect. After supplementation, 74% of the hemodialysis patients had post -dialysis homocysteine concentrations within the reference range (< 16 mu m ol/l). Homocysteine concentrations remained decreased in 20 patients four w eeks after withdrawal of folic acid supplementation. Conclusions: It is con cluded that supplementation with 2.5 or 5 mg folic acid has a similar effec t on homocysteine concentrations to supplementation regimens using 15 mg fo lic acid supplements. In contrast to the effect of folic acid supplementati on in subjects with normal renal function, folic acid supplementation does not normalize homocysteine concentrations in ESRD patients.