Effect of 22-oxacalcitriol on secondary hyperparathyroidism in hemodialysis patients

Objective A synthetic analogue of calcitriol, 22-oxacalcitriol (OCT), strongly suppresses parathyroid hormone (PTH) secretion. This study investigated the influence of OCT on PTH secretion and bone metabolism in 12 hemodialysis patients with secondary hyperparathyroidism. Methods OCT was intravenously injected after every hemodialysis session (three times weekly) for 22 weeks. The levels of the following parameters were measured: intact PTH, whole PTH, whole PTH/7-84 PTH ratio, adjusted calcium, phosphorus, alkaline phosphatase (ALP), bone-specific alkaline phosphatase (BAP), intact osteocalcin (OC), type I collagen carboxyterminal propeptide, tartrate-resistant acid phosphatase (TRAP), cross-linked C-terminal telopeptides of type I collagen, and interleukin-6. Patients The subjects were 12 hemodialysis patients (8 men and 4 women) with an intact PTH level of more than 460 pg/ml, a normal serum calcium level, and a serum phosphorus of less than 7 mg/dl. Results The levels of intact PTH, whole PTH, whole PTH/7-84 PTH ratio, ALP, BAP, OC, and TRAP were significantly decreased after OCT administration, while adjusted calcium was significantly increased. Serum phosphorus and the other parameters showed no significant changes. Conclusion OCT effectively suppressed the PTH level and bone metabolism parameters in hemodialysis patients with secondary hyperparathyroidism.