CKD Hyperphosphataemia — RACP Adult Medicine MCQ

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EasyNephrologyCKD HyperphosphataemiaRACP Adult Medicine

A 55-year-old man with CKD stage 5 (eGFR 12 mL/min/1.73 m²) not yet on dialysis has a phosphate of 2.4 mmol/L despite dietary restriction. What is the first-line phosphate binder?

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Correct answer: B — Calcium carbonate

Calcium-based phosphate binders (calcium carbonate with meals) remain first-line for hyperphosphataemia in CKD due to efficacy and low cost. However, total elemental calcium from binders should not exceed 1500 mg/day to avoid vascular calcification. Non-calcium-based binders (sevelamer, lanthanum) are preferred if serum calcium is elevated, PTH is suppressed, or vascular calcification is present. Aluminium-based binders are avoided due to aluminium toxicity risk.

Reference: KHA-CARI – 2013 – CKD-MBD Guidelines; KDIGO – 2017 – CKD-MBD Update