Influence of multivitamin regimen on urinary oxalate in home parenteral nutrition patients.

Background: High urinary oxalate levels have been associated with high ascorbic acid intakes. An alteration in the vitamin regimen for home parenteral nutrition (HPN) patients because of product discontinuation resulted in provision of 500 mg instead of 100 mg ascorbic acid per HPN day. This regimen was associated with high urinary oxalate levels. Purpose: To determine if a switch from a multivitamin regimen containing 500 mg to one containing 100 mg of ascorbic acid daily would reduce urinary oxalate levels. Methods: A 24-hour urine collection for oxalate was analyzed before switching the vitamin regimen back to 100 mg ascorbic acid and repeated 2 months after the change. A paired t test was conducted to compare measurements at baseline and at 2 months. Results: Overall, 18 patients completed both phases of this observational study. The initial urinary oxalate of 517 ± 63μ mol/day decreased to 425 ± 47 μmol/day after 2 months (p = .05). However, after applying the exclusion criteria, only 6 patients coul...