American Board of Internal Medicine (ABIM) Certification Practice Exam

What is typically required for most patients with CKD and hyperphosphatemia, in addition to dietary changes?

1. Increased hydration

2. Phosphate binders

3. Diuretics

4. Calcium supplements

The correct answer is: Phosphate binders

For patients with chronic kidney disease (CKD) and hyperphosphatemia, phosphate binders are commonly required alongside dietary modifications to effectively manage elevated phosphate levels. In CKD, the kidneys lose their ability to excrete phosphate, leading to an accumulation in the blood, which can result in complications such as vascular calcification and cardiovascular disease. Phosphate binders work by binding dietary phosphate in the gastrointestinal tract, preventing its absorption into the bloodstream. This mechanism helps lower serum phosphorus levels and is particularly important for patients with CKD as they may struggle to maintain normal phosphate levels through diet alone. While dietary changes are crucial in managing hyperphosphatemia, they may not be sufficient on their own, especially in patients with advanced stages of CKD. Other options, while relevant in certain contexts, do not address the primary issue of phosphate accumulation as directly as phosphate binders do. For instance, increased hydration can help with overall kidney function but does not directly lower phosphate levels, diuretics may manage fluid balance and electrolytes but are not specifically aimed at treating hyperphosphatemia, and calcium supplements are sometimes used to supplement calcium levels but can pose a risk when combined with phosphate binders in terms of vascular health. Therefore, phosphate bind