From the Guidelines

Hypercalcemia in Hemodialysis (HD) patients is harmful and should be avoided.

Hypercalcemia may be harmful in all GFR categories of CKD, including HD patients, as it can increase the Ca-P product index in blood, leading to arterial calcification and other complications 1.
The use of calcium-based phosphate binders should be restricted in patients with hyperphosphatemia across the CKD spectrum, including HD patients, to avoid hypercalcemia 1.
Treatment approaches for secondary hyperparathyroidism (SHPT) in HD patients should not include routine use of calcitriol or vitamin D analogues due to the increased risk for hypercalcemia, and instead, calcimimetics, calcitriol, or vitamin D analogues, or a combination of calcimimetics with calcitriol or vitamin D analogues should be used 1.

In patients with CKD G5D requiring PTH-lowering therapy, calcimimetics, calcitriol, or vitamin D analogues, or a combination of calcimimetics with calcitriol or vitamin D analogues should be used, with careful monitoring of serum calcium levels to avoid hypercalcemia 1.
Dialysate calcium concentration should be adjusted to avoid hypercalcemia, with a recommended concentration of 2.5 mEq/L, and lower concentrations (e.g., 1.5 to 2.0 mEq/L) may be used to treat hypercalcemia 1.

Hypercalcemia poses a risk for CKD patients, including HD patients, as it can increase the Ca-P product index in blood, leading to arterial calcification and other complications, and therefore, should be treated promptly and appropriately 1.
The primary cause of hypercalcemia should be sought and treated, rather than just adjusting dialysate calcium concentration 1.

From the Research

Hypercalcemia is a common complication in hemodialysis patients, with a prevalence of 38% in one study 2.
The use of calcium carbonate as a phosphorus binder, often in conjunction with calcitriol, can increase the risk of hypercalcemia in hemodialysis patients 2.
Hypercalcemia has been associated with an increased risk of infection-related and all-cause death in hemodialysis patients, with a hazard ratio of 2.34 for infection-related death in patients with higher serum calcium levels 3.
Hypercalcemia in hemodialysis patients can be caused by various factors, including renal osteodystrophy, aluminum toxicity, and immobility-induced hypercalcemia 4, 5.
The management of serum calcium concentration in hemodialysis patients is crucial, and identifying the cause and pathophysiological mechanisms involved can help guide treatment and prevention of disorders in serum calcium levels 6.
Treatment options for hypercalcemia in hemodialysis patients may include adjusting dialysate calcium levels, using calcitriol or other vitamin D analogs, and administering anti-resorptives such as calcitonin or bisphosphonates 2, 4, 5.