Adherence to treatment will be assessed by regular bill count. The starting dose of sevelamer and calcium acetate determined by replacing the phosphate binder used by the patient prior to the washout period on a gram to gram basis. The dose of phosphate binder should be titrated to achieve a serum phosphorus level in the target range of 1-1.6 mmol/L and a serum calcium level <2.6 mmol/L. The maximum elemental calcium dose/day in the calcium acetate arm will not exceed 1.5 g.