Paricalcitol Versus Ergocalciferol for Secondary Hyperparathyroidism in CKD Stages 3 and 4: A Randomized Controlled Trial

Background: The efficacy of 25-hydroxyvitamin D (25[OH]D) supplementation versus vitamin D receptor activators for the treatment of secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD) stages 3 or 4 and vitamin D deficiency is unclear. Study Design: Randomized controlled trial. Setting & Participants: 80 patients with CKD stages 3 or 4, 25(OH) D level <30 ng/mL, and SHPT in a single medical center. Intervention: Ergocalciferol, 50,000 units, titrated to achieve serum levels >= 30 ng/mL versus paricalcitol, 1 or 2 mu g/d, for 16 weeks. Outcomes: The occurrence of 2 consecutive parathyroid hormone (PTH) levels decreased by at least 30% from baseline. All analyses were intention to treat. Results: Baseline characteristics in the 2 groups were similar. 21 patients (53%) on paricalcitol and 7 patients (18%) on ergocalciferol treatment achieved the primary outcome measure (P = 0.002). After 16 weeks, PTH levels did not decrease significantly in patients receiving ergocalciferol, but were decreased significantly in those treated with paricalcitol (mean estimate of between-group difference over 16 weeks of therapy, 43.9 pg/mL; 95% CI, 11.2-76.6; P = 0.009). Serum 25(OH) D levels increased significantly after 16 weeks in only the ergocalciferol group, but not the paricalcitol group (mean estimate of between-group difference over 16 weeks of therapy, 7.08 ng/mL; 95% CI, 4.32-9.85; P < 0.001). Episodes of hyperphosphatemia and hypercalcemia were not significantly different between the 2 groups. Limitations: Lack of blinding and use of surrogate end points. Conclusions: Paricalcitol is more effective than ergocalciferol at decreasing PTH levels in patients with CKD stages 3 or 4 with vitamin D deficiency and SHPT. Am J Kidney Dis. 59(1): 58-66. Published by Elsevier Inc. on behalf of the National Kidney Foundation, Inc. This is a US Government Work. There are no restrictions on its use.