Effects of Lowering Dialysate Calcium Concentration on Bone Metabolic Markers in Hemodialysis Patients With Suppressed Serum Parathyroid Hormone: A Preliminary Study.

Although the Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommend a dialysate calcium concentration between 2.5 and 3.0 mEq/L, its optimal concentration remains unclear. A total of 53 hemodialysis patients with intact parathyroid hormone (PTH) levels <150 pg/mL were enrolled in this prospective observational study. A dialysate calcium concentration was converted from 3.0 to 2.75 mEq/L and bone metabolic markers including bone alkaline phosphatase (BAP) and tartrate-resistant acid phosphatase-5b (TRACP-5b) were examined. After 3 months, serum corrected calcium levels decreased (P < 0.001), while serum intact PTH, BAP and TRACP-5b levels increased (P < 0.05, P < 0.05 and P < 0.001, respectively). Multiple regression analyses showed that the amount of change in BAP was significantly associated with dialysis vintage (P < 0.01). In conclusion, the lowering of dialysate calcium concentration stimulated parathyroid gland and bone remodeling in hemodialysis patients with suppressed PTH, particularly with longer dialysis vintage.