Water-soluble vitamin levels in patients undergoing high-flux hemodialysisand receiving long-term oral postdialysis vitamin supplementation

The prescription of multivitamin supplements for dialysis patients is routi ne practice, but the doses prescribed differ greatly from one dialysis cent er to another. Few data are available concerning long-term vitamin suppleme ntation and its effects on patients either on high-flux hemodialysis or rec eiving postdialysis supplementation. For several years, we have systematica lly prescribed to our patients an oral postdialysis multivitamin supplement containing thiamine hydrochloride 100 mg, riboflavin 20 mg, pyridoxine hyd rochloride 50 mg, folic acid 6 mg, and ascorbic acid 500 mg. The aim of thi s study was to perform a cross-sectional long-term evaluation of the vitami n levels in patients who received this vitamin supplement for at least 12 m onths. We also were interested in investigating the plasma oxalic acid and total homocysteine levels associated with the long-term prescription of the se vitamin supplements. Thirty-three patients on high-flux dialysis were st udied. Vitamin levels and/or vitamin-dependent enzymatic activities were wi thin the normal range (N) in all patients. The mean results (+/- SD) were p lasma ascorbic acid 13.6 +/- 16.4 mg/L (N > 4), plasma folate 14.1 +/- 1.1 mug/L (N > 3), for vitamin B-1 alpha -ETK 1.02 +/- 0.02 (N < 1.18) and ETXo 100 <plus/minus> 13 U/L (N > 70), for vitamin B-2 alpha -EGR 1.00 +/- 0.07 (N < 1.52) and EGRo 1282 <plus/minus> 213 U/L (N > 672), and for Vitamin B -6, alpha -EGOT 1.34 +/- 0.10 (N < 1.8) and EGOTo 380 <plus/minus> 84 U/L ( N > 228). Plasma oxalic acid was higher than normal in all patients (mean = 61 +/- 15 mu mol/L, N < 33). However, all patients had oxalic acid levels within the range reported in the literature for patients not taking extra a scorbic acid. Mean total homocysteine was 24 <plus/minus> 8 mu mol/L with o nly 4 patients (12%) having normal levels (N < 15). In conclusion, the post dialysis supplement given provides adequate vitamin levels in almost all pa tients in the long term. Postdialysis prescription allows an optimal compli ance with the treatment, is well accepted by the patients, and is cost-effe ctive.