Prevalence of vitamin D [25(OH)D] deficiency and effects of supplementation with ergocalciferol (vitamin D2) in stage 5 chronic kidney disease patients

Objective: This study investigated the prevalence of vitamin D deficiency, its association with nutrition-related parameters, and the effects of ergocalciferol supplementation in stage 5 chronic kidney disease (CKD). Measures of interest included serum albumin, glycosylated hemoglobin (HgA1c), hemoglobin, phosphorus, corrected calcium, parathyroid hormone (iPTH), equilibrated normalized protein catabolic rate (enPCR), and quality-of life-survey physical component score (SF-36 PCS). Design and Setting: This retrospective study was conducted at five dialysis centers in western Massachusetts. Patient records were examined for a 6-month period in 2006, after initiation of a protocol to assess serum 25(OH)D and implement treatment with ergocalciferol if the level of serum 25(OH)D were <40 ng/mL. Results: Over 90% (i.e., 92.4%) of patients had vitamin D levels of less than 40 ng/mL; 80% had vitamin D levels at 31 ng/mL or less. Ergocalciferol supplementation (50,000 IU/week X 24) was associated with significant improvements in serum 25(OH)D from baseline (18.4 +/- 9.0 ng/mL; mean +/- SD) to 6 months (42.0 +/- 24.7 ng/mL.) (P < .0005). The level of glycosylated hemoglobin decreased from 6.9% +/- 1.9% at baseline to 6.4% +/- 1.5% at 6 months (P < .0005), while hemoglobin improved from 12.1 +/- 1.6 g/dL to 12.3 +/- 1.4 g/dL (P < .0005). Corrected calcium decreased from 8.7 +/- 0.8 mg/dL to 8.5 +/- 0.9 mg/dL at 6 months (P = .002). Phosphorus and iPTH exhibited a downward trend, though not significantly. Albumin remained stable, while enPCR increased (0.91 +/- 0.23 at baseline, vs. 0.98 +/- 0.32 at 6 months) (P = .01). The SF-36 PCS scores did not differ significantly from baseline (35.4 +/- 11.8) at 6 months (35.0 +/- 11.1). Conclusions: Vitamin D [25(OH)D] deficiency appears to be widely prevalent in stage 5 CKD. Repletion with ergocalciferol may assist in improving glycemic control in the management of diabetes. Additional research is needed to confirm these results and determine the optimal levels of serum 25(OH)D. (C) 2008 by the National Kidney Foundation, Inc. All rights reserved.