Long-term treatment for hyperphosphatemia due to renal failure includes which of the following?

• A. Calcium supplements
• B. Fluid restriction
• C. Magnesium supplements
• D. Increased dairy product intake

Answer: (A)

Managing hyperphosphatemia in kidney failure centers on reducing phosphate absorption from the gut. Long-term, calcium-based phosphate binders are commonly used for this purpose because they bind dietary phosphate in the intestines and form insoluble calcium phosphate that is excreted in the stool. This lowers circulating phosphate levels and helps prevent secondary hyperparathyroidism and bone problems that come with CKD.

Using calcium-based binders (represented here as calcium supplements) is effective because the key action is binding phosphate, not simply increasing calcium intake. The other choices don’t address phosphate absorption: limiting fluids helps with fluid status, not phosphate; magnesium supplements don’t bind phosphate and can cause other imbalances; and increasing dairy intake would raise phosphate load rather than reduce it.

Keep in mind calcium-based binders can cause hypercalcemia or vascular calcification with long-term use, so monitoring calcium and phosphate levels is important.