Dialysate Calcium Levels: Do They Matter?

Abstract

Background: Calcium (Ca) is an essential element that plays a critical role in many biological processes. In dialysis patients, the regulation of Ca balance is highly complex, given the absence of kidney function, endocrine disturbances and the use of drugs such as phosphate binders, vitamin D analogues, and calcimimetics. Also, the use of different dialysate Ca (DCa) baths has profound effect on Ca balance, which depends both on the difference between the Ca concentration in the bath and the serum of the patients, as on the ultrafiltration volume. Summary: The choice of DCa may have important short- and long-term consequences. While lower DCa (especially < 2.5 mEq/L) concentrations have been associated with an increased risk of sudden cardiac death in observational studies, DCa in the higher ranges (3.0 mEq/L and above) may contribute to vascular pathology. Intra-dialytic hemodynamics may also be affected by the choice of DCa. In general, lower DCa concentrations are associated with an increase, and higher DCa concentrations with a decrease in parathyroid hormone (PTH) levels. Preliminary data has suggested that a DCa of 2.75 mEq/L may help in obtaining a net zero intradialytic Ca balance in individual patients, but clinical experience is still limited. Key Message: The optimal Ca balance depends on multiple parameters including blood Ca levels, PTH and the use of phosphate binders and vitamin D analogues, as well as on the risk of hemodynamic stability and cardiac arrhythmias. Therefore, DCa prescription should be individualised. A DCa of 2.75 mEq/L may be useful adjunct for dialysis providers.

Dyselectrolytemia‑management and implications in hemodialysis (Review)

“…Calcium balance is achieved through complex hormone mechanisms, acting at intestinal, renal, and bone levels, through several substances: The parathyroid hormone (PTH), 1.25-dihydroxyvitamin D (calcitriol), fibroblast growth factor 23, calcitonine and estrogens (85).…”

<p>Efficacy and Safety of Evocalcet Evaluated by Dialysate Calcium Concentration in Patients with Secondary Hyperparathyroidism Undergoing Hemodialysis</p>

“…A limitation of this study is that the efficacy and safety of evocalcet and cinacalcet by dialysate calcium concentration were assessed only for 30 weeks. Given that patients with severe CKD undergo hemodialysis for longer than 30 weeks, and that their prognosis with respect to cardiovascular disease and MBDs is dependent on the calcium balance, 6 further studies are required to understand how different dialysate calcium concentrations affect the outcome of long-term treatment with evocalcet and cinacalcet. Another limitation of this study is the inclusion of a specific patient population in Japan.…”

“…5 It is therefore clear that maintaining a balance in the levels of phosphate, calcium, and PTH is critical in patients with secondary hyperparathyroidism. 6 The Japanese Society for Dialysis Therapy recommends target ranges for serum PTH, calcium, and phosphate levels in its clinical practice guideline for the management of CKD-MBDs, including secondary hyperparathyroidism. 7 Calcium-sensing receptors detect extracellular calcium concentrations.…”

Intradialytic Calcium Kinetics and Cardiovascular Disease in Chronic Hemodialysis Patients

“…Current KDIGO guidelines [1] recommend a dialysate calcium (dCa) concentration of 2.5-3 mEq/L in order to avoid excessive intradialytic calcium (Ca) loading as this has been associated with an elevated cardiovascular (CV) risk [2]. However, we and others have previously demon-DOI: 10.1159/000508060 strated that even under these precautions calcium loading during dialysis occurs in a relevant number of chronic hemodialysis (HD) patients.…”