Why take phosphate binders for Hyperphosphatemia?

From the Guidelines

Phosphate binders should only be taken by patients with overt hyperphosphatemia, as current evidence does not show benefit to maintaining normal serum phosphate levels in patients not receiving dialysis, and there are safety concerns associated with aggressive phosphate-lowering therapy. The primary goal of using phosphate binders is to control high phosphate levels in the blood, particularly in people with kidney disease, by binding to phosphate from food in the digestive tract and preventing it from being absorbed into the bloodstream 1.

Key Considerations for Phosphate Binder Use

• Phosphate binders should be used with caution, considering the potential risks and benefits, and treatment approaches should be based on serial assessments of biochemical variables (serum phosphate, calcium, and PTH) taken together 1.
• The use of calcium-based phosphate binders should be restricted in patients with hyperphosphatemia across the CKD spectrum, due to the risk of hypercalcemia 1.
• Treatment approaches for secondary hyperparathyroidism (SHPT) in patients not receiving dialysis should not include routine use of calcitriol or vitamin D analogues, due to the increased risk for hypercalcemia 1.

Practical Guidance on Phosphate Binder Administration

• Phosphate binders should be taken with meals or snacks to effectively bind dietary phosphate.
• The typical dosing varies by medication type, and should be adjusted based on blood phosphate levels.
• Patients should take these medications consistently with meals, follow dosing instructions carefully, and maintain regular blood tests to monitor phosphate levels.
• Dietary phosphate restriction is also important while using these medications for optimal results.

From the FDA Drug Label

Patients with ESRD retain phosphorus and can develop hyperphosphatemia. High serum phosphorus can precipitate serum calcium resulting in ectopic calcification Hyperphosphatemia also plays a role in the development of secondary hyperparathyroidism in patients with ESRD. Calcium acetate, when taken with meals, combines with dietary phosphate to form an insoluble calcium phosphate complex, which is excreted in the feces, resulting in decreased serum phosphorus concentration.

Phosphate binders, such as sevelamer hydrochloride and calcium acetate, are taken to:

• Decrease serum phosphorus levels
• Prevent hyperphosphatemia and its complications, including:
  • Ectopic calcification
  • Secondary hyperparathyroidism
• Control serum phosphorus levels in patients with end-stage renal disease (ESRD) 2, 3

From the Research

Reasons for Taking Phosphate Binders

• Phosphate binders are used to reduce positive phosphate balance and lower serum phosphate levels in people with chronic kidney disease (CKD) to prevent progression of chronic kidney disease-mineral and bone disorder (CKD-MBD) 4.
• The goal of phosphate binder treatment is to control hyperphosphatemia, which is associated with elevated parathormone levels, abnormal bone mineralization, extraosseous calcification, and increased risk of cardiovascular events and death 5.
• Phosphate binders can help to reduce the risk of vascular calcification, bone fractures, and cardiovascular mortality in CKD patients 6, 7.

Benefits of Phosphate Binders

• Sevelamer, lanthanum, iron, and calcium-based phosphate binders can lower serum phosphate levels in CKD patients 4.
• Phosphate binders may reduce the risk of death, cardiovascular events, and bone fractures in CKD patients, although the evidence is uncertain or inestimable for some outcomes 4, 6, 5.
• Iron-based phosphate binders, such as sucroferric oxyhydroxide, may be as effective as sevelamer in reducing phosphatemia with a similar safety profile and lower pill burden 6.

Considerations for Phosphate Binder Selection

• The choice of phosphate binder should be individualized based on factors such as CKD stage, cardiovascular disease, severity of secondary hyperparathyroidism, concomitant medications, life expectancy, and patient compliance 8.
• Phosphate binders have different safety profiles, with some agents associated with an increased risk of hypercalcemia, calcifications, or gastrointestinal symptoms 4, 5.
• New phosphate binders, such as colestilan and ferric citrate, are being developed and may offer alternative treatment options for CKD patients 5, 7.