Comparison of Calcium Carbonate and Aluminium Hydroxide as Phosphate Binders on Biochemical Bone Markers, PTH(1-84), and Bone Mineral Content in Dialysis Patients

Abstract

Bone mineral content, estimated by single-photon absorptiometry of the forearm, serum values of intact parathyroid hormone (PTH(l–84)), osteocalcin, alkaline phosphatase, 1,25-dihydroxycholecalciferol (1,25(OH)₂D3), and aluminium were determined during treatment with calcium carbonate (CaCO₃) or aluminium hydroxide (Al(OH)₃) in 11 dialysis patients participating in a randomised cross-over study. Each treatment period lasted 6 months. Serum phosphorus was maintained in the range 1.5–2.0 mmol/1. During AI(OH)₃ treatment bone mineral content (BMC) decreased by 11% per half-year (mean), but only by 3% per half-year during CaCO₃ treatment (P3 periods the following differences were found: serum calcium increased during CaCO₃ treatment, PTH(1–84) decreased (79% of initial values during CaCO₃ versus 196% during Al(OH)₃, mean area under curve, PPPP2D3 remained unchanged in both periods. No increase in soft-tissue calcification was demonstrated on X-ray of the shoulders in any of the periods. Thus, CaCO₃ treatment seems to slow down loss of bone mineral content, and using CaCO₃ as phosphate binder may have a more beneficial effect on the progression of uraemic bone disease than Al(OH)₃ due to the reduction of hyperparathyroidism and bone turnover.