Which statement about phosphate binders is true?

• A. They are used to manage serum phosphate in CKD by binding phosphate in the gut.
• B. They increase phosphate absorption in the gut.
• C. They are used to treat hyperkalemia.
• D. They are a type of diuretic.

Answer: (A)

Phosphate binders are used to control serum phosphate in CKD by binding dietary phosphate in the gut so it cannot be absorbed. By forming an insoluble complex that is excreted in the stool, they lower the amount of phosphate entering the bloodstream, which helps prevent complications like bone-mineral disorders and vascular calcification in CKD. They are taken with meals so they have phosphate to bind. They do not increase phosphate absorption, and they are not used to treat hyperkalemia or act as diuretics.