Long-term effect of different dialysate calcium concentrations on parathyroid hormone levels in hemodialysis patients.Ren Fail. 2008; 30(10):943-51.RF
The appropriate dialysate calcium concentration (D[Ca]) for hemodialysis (HD) therapy has not yet reached a consensus. We have conducted a prospective control study for five years on the effects of different D[Ca] on serum intact parathyroid hormone (iPTH) levels. Patients were divided into three groups receiving different D[Ca] therapies: the low-Ca (D[Ca] = 2.5 mEq/L; N = 96), mid-Ca (D[Ca] = 3.0 mEq/L; N = 121), and high-Ca (D[Ca] = 3.5 mEq/L; N = 82) groups. After five years' study, only 41 patients in the low-Ca group, 34 in the mid-Ca group, and 32 in the high-Ca group completed the study. The results demonstrated that serum corrected calcium concentrations were significantly lower in the low-Ca group compared with other groups in years 3 and 4, although the products of corrected calcium time phosphate did not show difference between each group.(Delta)serum alkaline phosphatase ((Delta)Alk-p) to baseline levels increased significantly after the fourth year in all three groups (p < 0.05). Serum (Delta) iPTH only increased significantly after the fourth year in the low-Ca group (p < 0.05) but not in the other groups. There were no significant differences in the extent of (Delta)Alk-p and (Delta)iPTH between the groups. Cox proportional methods also showed no difference in cumulative survival between the groups. In conclusion, our results demonstrate that compared with the other two groups of D[Ca], long-term use of D[Ca] of 2.5 mEq/L was associated with relatively lower serum calcium concentration. Perhaps this was related to a greater extent of iPTH concentration elevation after five years.