<qa>  How many hemodialysis patients will be enrolled in this prospective controlled study?Sample size calculations were based on previously reported changes in coronary artery calcification scores in hemodialysis patients during time 90 power with a two-sided, alpha error rate of 5. Four hundred fifty-seven hemodialysis patients, taking drop-out rate into consideration, will be enrolled in this prospective-controlled study.The cases already being treated with calcium-based phosphate binder and dialysate containing 1.75 or 1.5 mmolL calcium will be enrolled from eight hemodialysis centers.The cases will be randomized to two arms: 