Effect of Sevelamer Hydrochloride on Markers of Bone Turnover in Japanese Dialysis Patients with Low Biointact PTH Levels

Abstract

Background: In hemodialysis patients, adynamic bone disease has been reported to be closely associated with low levels of parathyroid hormone (PTH) due to exposure to high levels of serum calcium following the administration of calcium carbonate (CaCO₃) or vitamin D agents. This study was conducted to clarify the therapeutic effect of a non-calcemic phosphate binder, sevelamer hydrochloride (sevelamer), for hypoparathyroidism in hemodialysis patients with or without diabetes mellitus.
Methods: Based on entry criteria, 40 Japanese chronic hemodialysis patients (22 males and 18 females with a mean age of 60.6, 14 diabetic patients and 26 non-diabetic patients) were switched from CaCO₃ to sevelamer for 48 weeks. Serum calcium, phosphate, intact (i) PTH and PTH-(1-84) were analyzed. Bone remodeling activity was evaluated by determining intact osteocalcine (iOC), bone-specific alkaline phosphatase (BAP).
Results: The switch from CaCO₃ to sevelamer significantly decreased the serum levels of calcium, resulting in the elevation of iPTH levels from 31±18 pg/mL to 95±96 pg/mL by 48 weeks. In contrast, serum phosphate levels remained similar to those in patients with CaCO₃ treatment. Concomitantly, the levels of BAP and iOC were elevated. Further, these beneficial effects on bone turnover were observed in both diabetic and non-diabetic patients.
Conclusion: Sevelamer reduced the calcium concentration and thereby increased PTH levels, resulting in the improvement of markers of bone turnover. The administration of sevelamer is of therapeutic benefit for the improvement of bone remodeling activity even in hemodialysis patients with diabetes.