Effects of Dialysate Calcium Concentration and Calcitriol on Bone Metabolism in Hemodialysis Patients

Youm, Ji Youn; Kim, Hyun Chul; Lee, Young Chul; Choi, Jong Wook; Park, Joon Sung; Lee, Chang Hwa; Kang, Chong Myung; Kim, Gheun Ho

Abstract

BACKGROUND/AIMS
Whereas higher dialysate calcium (Ca) levels may pose a risk of hypercalcemia, lower levels may induce a negative Ca balance. We evaluated the effect of lowering dialysate Ca levels from 1.75 to 1.5 mmol/L and explored the appropriate use of calcitriol to regulate bone metabolism in hemodialysis patients.
METHODS
The dialysate Ca levels of 36 patients were reduced from 1.75 to 1.5 mmol/L. They were divided into three groups according to basal intact parathyroid hormone (iPTH) level (group 1, iPTH < 150 pg/mL, n = 21; group 2, iPTH 150-300 pg/mL, n = 7; group 3, iPTH > 300 pg/mL, n = 8). Data were collected at 3-month intervals for 1 year.
RESULTS
Throughout the study period, no significant difference in phosphate binders, serum Ca, phosphorus (P), or Ca x P products was observed among groups. However, iPTH, alkaline phosphatase (AP), and calcitriol dosage patterns differed among groups. In group 1, iPTH and AP increased significantly over 12 months (p = 0.01). In group 2, iPTH and AP showed no significant changes. In group 3, iPTH and AP declined significantly over 12 months (p = 0.02). Calcitriol dosage did not change in groups 1 and 2, but increased significantly in group 3 (p = 0.001).
CONCLUSIONS
After converting hemodialysate Ca levels from 1.75 to 1.5 mmol/L, the initially different iPTH concentrations converged to a modestly elevated level. The use of 1.5 mmol/L hemodialysate Ca may thus be appropriate for both high- and low-turnover bone disease if phosphate binders and calcitriol are combined appropriately.