Relationship between the effect of eldecalcitol and serum 25(OH)D level

Area of Science:

• Endocrinology
• Bone Metabolism
• Pharmacology

Background:

• Osteoporosis poses a significant fracture risk, particularly in older adults.
• Vitamin D metabolites are crucial for bone health, but their optimal levels for treatment efficacy are debated.
• Eldecalcitol has shown promise in increasing bone mineral density and reducing fractures compared to alfacalcidol.

Purpose of the Study:

• To investigate whether the fracture risk reduction by eldecalcitol is influenced by serum 25-hydroxyvitamin D (25(OH)D) levels.
• To compare the efficacy of eldecalcitol versus alfacalcidol in increasing bone mineral density (BMD) across different baseline 25(OH)D levels.
• To assess the impact of eldecalcitol on vitamin D metabolite levels and parathyroid hormone.

Main Methods:

• Analysis of data from a 3-year randomized double-blind clinical trial comparing eldecalcitol and alfacalcidol.
• Patients were stratified into tertiles based on serum 25(OH)D levels at 6 months post-treatment initiation.
• Measurements included lumbar and hip BMD, fracture incidences, serum 25(OH)D, serum 1,25(OH)2D, and parathyroid hormone.

Main Results:

• Eldecalcitol significantly increased lumbar and hip BMD more than alfacalcidol across all 25(OH)D tertiles.
• Fracture incidences tended to be lower with eldecalcitol compared to alfacalcidol in most tertiles.
• Eldecalcitol treatment reduced serum 1,25(OH)2D by approximately 50% without affecting serum 25(OH)D or parathyroid hormone levels.

Conclusions:

• Eldecalcitol demonstrates efficacy in increasing BMD and reducing osteoporotic fractures compared to alfacalcidol, irrespective of serum 25(OH)D levels (≥20 ng/mL).
• Eldecalcitol does not alter serum 25(OH)D levels.
• Further research is needed to determine eldecalcitol's effectiveness in patients with vitamin D deficiency (serum 25(OH)D <20 ng/mL).