Effectiveness of calcium acetate as a phosphate binder in patients undergoing continuous ambulatory peritoneal dialysis

BY Choy, WK Lo, IKP Cheng
Division of Nephrology, Department of Medicine, Queen Mary Hospital, Pokfulam, Hong Kong

We compared the effectiveness of calcium acetate as a phosphate binder with that of calcium carbonate by substituting one for the other in patients undergoing continuous ambulatory peritoneal dialysis. Twenty patients who had been receiving calcium carbonate as a phosphate binder were instead given calcium acetate, initially with two thirds of the previous dose of elemental calcium. The calcium acetate dose was adjusted to achieve adequate calcium-phosphate balance; 65.6% of the previous dose of elemental calcium in calcium carbonate was required. Eighteen of the 20 patients completed the 3-month study. There were no significant differences in the pre-study and study levels of serum phosphate (1.81�0.04 [SEM] versus 1.89�0.06 mmol/L), corrected serum calcium (2.54�0.04 versus 2.57�0.03 mmol/L), calcium phosphate product (4.60�0.15 versus 4.87�0.18), serum alkaline phosphatase (64.75�4.17 versus 69.94�3.77 U/L), and serum parathyroid hormone (122�31 versus 124�27 ng/L). Three patients developed a total of five episodes of hypercalcaemia (corrected calcium level >/=2.85 mmol/L) and four other patients developed gastrointestinal upset. Calcium acetate can thus achieve similar phosphate control to calcium carbonate, using 65.6% of the dose of elemental calcium in calcium carbonate; however, its clinical superiority was not demonstrated in this study.

Hong Kong Med J 1998;4:23-6

Key words: Acetic acids/therapeutic use; Calcium carbonate/therapeutic use; Patient compliance; Peritoneal dialysis, continuous ambulatory; Phosphates/blood