Can Low-Calcium Peritoneal Dialysis Solution Safely Replace the Standard Calcium Solution in the Majority of Chronic Peritoneal Dialysis Patients?

Objective To evaluate the use of low-calcium solution as the standard solution in chronic peritoneal dialysis patients.Design Prospective long-term follow-up study over a one-year period.Setting University hospital.Interventions The change of the calcium concentration of the dialysate from 1.75 mmollL to 1.25 mmollL.Main Outcome Measures Serum calcium and phosphorus concentration and intact parathyroid hormone (iPTH).Patients Fifty normo and hypercalcemic patients using the standard 1.75 mmollL calcium solution.Results Serum ionized calcium (iCa) decreased significantly during the first six months, resulting in a significant increment of iPTH (baselinevalue: 0.9 79, median 9.4 pmollL; at six months: 1.1 -111, median 20.6 pmollL; p < 0.05). In 28 patients completing the study, iPTH remained significantly elevated, despite high normal iCa. At similar changes of iCa, patients with baseline iPTH > 20 pmollL showed a significantly higher increase in iPTH than patients with low iPTH (24.0 vs 5.0; p < 0.01), despite a more than doubled dose of alfacalcidol and calcium carbonate (mean dose of 1580 increased to 3277 mg/day). During the follow-up, 21 episodes of hypercalcemia were observed. Phosphorus control was adequate.Conclusions Low-calcium solution cannot be used as a standard solution, especially in patients with iPTH levels indicating mild or severe hyperparathyroidism, because in these patients iPTH may rise further.