Background: Vitamin D deficiency contributes to secondary hyperparathyroidism, which occurs early in chronic kidney disease (CKD). Objectives:... » More

Background: Vitamin D deficiency contributes to secondary hyperparathyroidism, which occurs early in chronic kidney disease

(CKD).

Objectives: We aimed to determine whether high-dose cholecalciferol supplementation for 1 y in early CKD is sufficient to maintain

optimal vitamin D status (serum 25-hydroxyvitamin D [25(OH)D] concentration $30 ng/mL) and decrease serum parathyroid hormone

(PTH). A secondary aim was to determine the effect of cholecalciferol on blood pressure and serum fibroblast growth factor-23

(FGF23).

Design: This was a double-blind, randomized, placebo-controlled trial. Forty-six subjects with early CKD (stages 2–3) were supplemented with oral cholecalciferol (vitamin D group; 50,000 IU/wk for 12 wk followed by 50,000 IU every other week for 40 wk) or

a matching placebo for 1 y.

Results: By 12 wk, serum 25(OH)D increased in the vitamin D group only [baseline (mean 6 SD): 26.7 6 6.8 to 42.8 6 16.9 ng/mL;

P , 0.05] and remained elevated at 1 y (group-by-time interaction: P , 0.001). PTH decreased from baseline only in the vitamin D

group (baseline: 89.1 6 49.3 to 70.1 6 24.8 pg/mL; P = 0.01) at 12 wk, but values were not significantly different from baseline at

1 y (75.4 6 29.5 pg/mL; P = 0.16; group-by-time interaction: P = 0.09). Group differences were more pronounced in participants with

secondary hyperparathyroidism (group-by-time interaction: P = 0.004). Blood pressure and FGF23 did not change in either group.

Conclusions: After 1 y, this oral cholecalciferol regimen was safe and sufficient to maintain serum 25(OH)D concentrations and prevent

vitamin D insufficiency in early CKD. Furthermore, serum PTH improved after cholecalciferol treatment, particularly in patients

who had secondary hyperparathyroidism. This trial was registered at clinicaltrials.gov as NCT00427037.

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