Is 2.5 mEq/L the optimal calcium concentration of dialysate in the use of sevelamer hydrochloride? A study of the dialysate calcium concentration recommended by K/DOQI guidelines.

We tested the effect of three different dialysate calcium concentrations on calcium-phosphorus metabolism during the use of sevelamer hydrochloride. After a calcium-containing phosphate binder was switched to sevelamer, the serum calcium, phosphorus, and intact parathyroid hormone levels and the markers of bone turnover were measured in the patients whose dialysate calcium concentrations were 2.5, 2.75, and 3.0 mEq/L. As a result, in the 2.75-mEq/L group, the serum calcium concentrations decreased and the intact parathyroid hormone level increased significantly. In the 2.5-mEq/L group, transient hypocalcemia occurred and the levels of both bone-alkaline phosphatase and osteocalcin increased. In the 3.0-mEq/L group, the serum calcium concentrations did not change significantly and only bone-alkaline phosphatase increased. If a calcium-containing phosphate binder is completely switched to sevelamer, dialysis using a dialysate calcium concentration below 3.0 mEq/L may result in hypocalcemia and acceleration of bone turnover.