Neither folic nor folinic acid normalize homocysteine levels in hemodialysis patients

Aims: A greater decrease in total homocystein (tHcy) has been reported in patients on hemodialysis (HD) following the administration of reduced forms of folic acid (FA), however, the effect of the administration of moderated doses of oral levofolinic acid has not been compared with that of FA. We decided to perform a study to evaluate the therapeutic effectiveness of oral levofolinic acid, the pharmacologically active form of folinic acid in our population of HD patients already on treatment with oral FA and vitamin B-6. Material and methods: We undertook a prospective study in HD patients who had been receiving oral supplements of both FA 5 mg every 48 hours and vitamin B-6 40 mg every 7 days during at least 6 months, with a 17% initial decrease of tHcy levels. Patients matched for age, sex and time on HD were assigned to 1 of 2 groups: Those in group A continued to receive their previous supplements while in group B, FA was substituted by calcium levofolinate 5 mg given orally every 48 hours. The following parameters were measured at baseline and at month 6: urea kinetic model and concentrations of plasma albumin, C-reactive protein, folate, vitamin B-12, pyridoxal phosphate and tHcy. Results: Group A: 30 patients aged 63.4 (57.9, 68.9) years, with a time on HD of 23.4 (15.8, 30.8) months, group B: 32 age-matched patients 66.2 (62.1, 70.3) years old, with a time on HD of 23.8 (16.7, 30.9) months. No differences were found either in folate levels (72.7 (47.9, 97.5) vs. 71.9 (44.0. 99.9) ng/ml), tHcy (23.5 (21.1, 25.9) vs. 23.3 (20.8, 25.8) mumol/l), or any other study variables. In the 2 groups a significant reduction in both residual renal function (RRF) and vitamin B-12 levels was observed after supplementation, but no changes in tHcy values, folate levels or any of the other parameters were found. The prevalence of hyperhomocysteinemia in group A was 93.3% at study start and 100% at month 6, in group B the corresponding values were 93.8% and 96.9%. After 6 months, multiple regression analysis showed that tHcy levels were not influenced by the type of treatment (p = 0.543). Conclusions: After 6 months of calcium-levofolinate supplementation tHcy levels did not decrease and were similar to those in patients given the same dose of FA.