Differences in corrective mode for divalent ions and parathyroid hormone between standard- and low-calcium dialysate in patients on continuous ambulatory peritoneal dialysis--result of a nationwide survey in Japan

Abstract

Background: In patients on continuous ambulatory peritoneal dialysis (CAPD), dialysate calcium concentration has a strong influence on correction of serum calcium, phosphorus, and parathyroid hormone (PTH); however, the optimal concentration of Ca in PD solution is still uncertain. The aim of the survey reported here was to evaluate the prevalence of patients treated with standard- [SCD (approximately 3.25 - 4.0 mEq/L)] or low-calcium [LCD (approximately 1.8 - 2.5 mEq/L)] dialysate and differences in the clinical effects for correction of abnormalities in divalent ions and PTH.

Materials and methods: We used a questionnaire to survey 333 peritoneal dialysis facilities nationwide in Japan. Then, we analyzed serum Ca, P, and PTH levels and the prescription rates for CaCO(3) as a P binder and for vitamin D (VitD) analogs.

Results: The 2384 CAPD patients enrolled in this analysis had a mean age of 60.5 +/- 14.2 years and a mean duration of CAPD of 44.1 +/- 39.2 months. The prevalences of SCD, LCD, and combination of SCD and LCD were, respectively, 49%, 50%, and 1% at initiation, and 40%, 38%, and 22% at the time of the survey. In 735 and 876 patients respectively, LCD and SCD had been prescribed from initiation to the time of the survey. In these two groups, we observed no difference in initiation and current serum levels of Ca and P. But prescription rates for CaCO(3) and VitD analogs were higher in the LCD group than in the SCD group, and PTH levels were higher in the LCD group than in the SCD group.

Conclusions: A beneficial effect of LCD was revealed in the increased doses of CaCO(3) and VitD analogs seen in that group without the occurrence of hypercalcemia; however, PTH levels in that group were not maintained within an acceptable range. The survey suggests that more serious attention should be paid to the Ca concentration in peritoneal dialysate so as to lessen mineral and PTH disorders in CAPD.