[Effect of salmon calcitonin on bone mineral density and calcium-phosphate metabolism in chronic hemodialysis patients with secondary hyperparathyroidism]

Abstract

The aim of the study was to evaluate the effect of salmon calcitonin on bone mineral density, parathyroid and thyroid C cells, and calcium-phosphate metabolism in chronic hemodialysis patients with uremic hyperparathyroidism. Forty five patients with serum 1-84 PTH >220 pg/ml were divided into 2 groups: group I (n = 25), treated with intranasal salmon calcitonin (200 IU, thrice a week) and control group II (n = 20). Patients received calcium carbonate (up to 6 g/d) alone or with aluminum hydroxide (up to 3 g/d) as phosphate binders; dialysate calcium was 1.75-2 mmol/l. The observation period was 12 months. The following parameters were measured: bone mineral density (BMD) with dual-energy X-ray absorptiometry in: lumbar spine (L2-L4), femoral neck and total body, before and after the study; serum endogenous calcitonin, before and after the study; serum PTH, alkaline phosphatase and total hydroxyproline, before and after 1, 3, 6, and 12 months; and serum calcium and phosphate monthly. During 12 months of the study, a substantial reduction in BMD was observed in all examined regions in group II (-2.8 +/- 2.1%; p<0.01 in L2-L4, -2.4 +/- 2.0%; p<0.01 in femoral neck, and -1.9 +/- 1.4%; p<0.01 in total body), whereas in group I a slight increase of bone mineral was noted, however insignificant. The inhibition of bone resorption was accompanied by a marked decrease in serum hydroxyproline. No changes in parathyroid activity were noted nor any decrease in serum phosphate. The treatment had no influence on serum endogenous calcitonin; initial concentrations were elevated in 47% of patients.

Conclusion: Intranasal salmon calcitonin: 1) has no influence on bone mineralization in dialysis patients with uremic hyperparathyroidism; 2) has no significant effect on serum phosphate concentration; 3) provided adequate calcium supplementation doesn't stimulate parathyroid glands; 4) has no influence on endogenous calcitonin secretion.