Background: This short-term prospective study aimed to assess the effects of treatment with calcidiol (25-hydroxycholecalciferol) or calcitriol in the subset of hemodialysis patients characterized by stable low serum levels of parathyroid hormone (PTH) or affected by hypoparathyroidism after total parathyroidectomy (PTx).
Methods: Two groups were created according to baseline serum levels of 25-hydroxyvitamin D (25(OH)D): group A (12 patients): <15 ng/mL; group B (12 patients): >15 ng/mL. They underwent a 6-month treatment with oral calcidiol (group A) or oral calcitriol (group B).
Results: Group A showed a statistically significant increase in the serum levels of calcium corrected for serum albumin (cCa), phosphorus (P), total alkaline phosphatases (ALP), PTH and 25(OH)D. Group B showed a statistically significant increase in serum levels of cCa and P. A statistically significant decrease in serum levels of ALP and 25(OH)D was observed. Baseline serum 25(OH)D levels were 12.6 + 3.8 ng/mL in group A and 23.0 + 5.0 ng/mL in group B (p<0.0001). After 6 months, they increased to 38.3 + 21.0 ng/mL in group A (p<0.01) and decreased to 16.9 + 5.8 ng/mL in group B (p<0.01).
Conclusions: Treatment with oral calcitriol was associated with a decrease in the serum levels of ALP and 25(OH)D; treatment with oral calcidiol was associated with more physiological serum levels of 25(OH)D and with an increase in the serum levels of ALP and PTH: whether the statistically significant differences in the biochemical parameters achieved with the 2 treatments have a clinical relevance, remains a matter of debate.