Efficacy of High vs. Conventional Ergocalciferol Dose for Increasing 25-Hydroxyvitamin D and Suppressing Parathyroid Hormone Levels in Stage III-IV CKD with Vitamin D Deficiency/Insufficiency: A Randomized Controlled Trial.

Background: Vitamin D deficiency/insufficiency is common in chronic kidney disease (CKD) patients and it contributes to secondary hyperparathyroidism, which occurs early in CKD. It is not clear whether the Kidney Disease Outcomes Quality Initiative (K/DOQI) recommended doses of ergocalciferol are adequate for correction of vitamin D insufficiency and hyperparathyroidism.

Objective: To evaluate the parathyroid hormone (PTH)-lowering effect, safety, and tolerability of high-dose ergocalciferol compared with conventional-dose ergocalciferol in CKD subjects.

Material And Method: We enrolled CKD stage III-IV patients who had 25-hydroxyvitamin D (25-OH-D) level <30 ng/mL. The patients were randomized into two groups, control group treated with ergocalciferol as recommended by K/DOQI guidelines, and treatment group treated with double dosage of ergocalciferol from the recommendation. We compared serum 25-OH-D, intact-PTH, phosphate, calcium, and bone biomarker levels, during the 8-week intervention.

Results: Sixty-eight patients were included (34 controls and 34 treatments). Baseline characteristics of both groups were similar except calcium level 9.12 ± 0.56 mg/dL in control group and 9.44 ± 0.38 mg/dL in treatment group (p = 0.009), but not clinically significant. At the end of the 8-week, the mean 25-OH-D level significantly increased from 20.99 ± 6.68 to 33.41 ± 8.92 ng/mL in the treatment group (p = 0.001) and increased from 20.84 ± 7.21 to 23.42 ± 7.89 ng/mL in the control group (p = 0.026). There was also a significantly greater increase of 25-OH-D levels in the treatment group. Additionally, PTH levels significantly decreased from 90.75 ± 67.12 to 76.40 ± 45.97 at 8 weeks (p = 0.024) in the treatment group, and there was no change in the control group (97.14 ± 83.52 vs. 101.13 ± 95.03 pg/mL, p = 0.546). Serum calcium, phosphate, and adverse effects did not significantly change in either group throughout the study.

Conclusion: In addition to improving vitamin D levels, oral high-dose ergocalciferol was safe and had a beneficial effect in decreasing PTH in patients with stage III-IV of CKD.