Abstract: Objective To investigate the effect of low-calcium dialysate(1.25mmol/L) on calcium and phosphate metabolism and parathyroid hormone secretion in hemodialysis(HD) patients with secondary hypoparathyroidism. Methods Twenty-six HD patients with low level of intact parathyroid hormone (iPTH＜100pg/ml) were treated with 1.25mmol/L calcium dialysate for 12 months. Calcium carbonate were given as phosphrous binder or calcium supplement， and the active Vitamin D were not applied. Results Serum calcium concentration decreased significantly from (2.63±0.29) mmol/L at baseline to (2.38±0.13)mmol/L after 3 months and remained in this range thereafter. Calcium-phosphorous product(Ca x P)had the same change as calcium from(53.14±13.67)mg2/dl2 at baseline to (46.74±9.47)mg2/dl2 after 3 months(P＜0.05). iPTH level increased significantly from baseline (57.79±36.61)pg/ml to a maximum of (131.12±76.17)pg/ml at 6 months（P＜0.05）,then remained stable. Conclusion The treatment with 1.25mmol/L calcium dialysate effectively decreased serum calcium and Ca x P, stimulated the secretion of parathyroid hormone, and is suitable for HD patients with a relative PTH deficiency, who have tendency to hypercalcemia and calciphylaxis.

Key words: Hemodialysis, Parathyroid hormone