Individualization of Dialysate Calcium Concentration According to Baseline Pre-Dialysis Serum Calcium

BACKGROUND: A positive calcium balance may contribute to vascular calcification, while a negative balance increases iPTH. We explored the impact of different dialysate calcium concentrations on bone and mineral metabolism parameters according to pre-dialysis serum calcium levels. RESULTS: Fifty-six hemodialysis patients were dialyzed with 3.0 or 2.5 mEq/l dialysate [calcium] in a crossover study of two weeks. Bone mineral metabolites were measured prior to and following the hemodialysis session. A 3.0 mEq/l dialysate [calcium] increased more post-dialysis total calcium and ionized calcium than 2.5 mEq/l dialysate [calcium]. The mildest dialysis-induced changes in calcium and PTH were observed in patients with pre-dialysis serum calcium <8.75 mg/dl dialyzed with 2.5 mEq/l dialysate [calcium] and in patients with pre-dialysis serum calcium >9.15 mg/dl dialyzed with 3.0 mEq/l calcium dialysate. CONCLUSION: In conclusion, the individualization of dialysate calcium concentration according to baseline pre-dialysis serum calcium may prevent major excursions in post-dialysis serum calcium and iPTH levels. SHORT SUMMARY: High calcium dialysate may increase serum calcium in hemodialysis patients, while low dialysate calcium may increase PTH. Individualization of dialysate calcium according to predialysis serum calcium levels may prevent or decrease unwanted excursions of both serum calcium and PTH.