How should I manage a patient with hyperphosphatemia (elevated phosphate levels)?

From the Guidelines

Management of hyperphosphatemia involves dietary phosphate restriction, phosphate binders, and treating the underlying cause, with the goal of lowering elevated phosphate levels toward the normal range, as suggested by the Kidney Disease: Improving Global Outcomes 2017 clinical practice guideline update 1. To manage hyperphosphatemia, the following steps can be taken:

• Limit dietary phosphate intake to 800-1000 mg/day by reducing consumption of processed foods, dairy products, and cola beverages.
• Prescribe phosphate binders to be taken with meals:
  • Calcium-based binders (calcium carbonate 500-1500 mg TID with meals or calcium acetate 667 mg, 2-3 tablets with meals) for patients without hypercalcemia.
  • Non-calcium binders like sevelamer (800-1600 mg TID with meals), lanthanum carbonate (500-1000 mg TID with meals), or ferric citrate (1 gram TID with meals) for those with hypercalcemia or vascular calcifications.
• Address the underlying cause, which is often chronic kidney disease requiring dialysis optimization.
• For acute severe hyperphosphatemia, consider hemodialysis.
• Monitor serum phosphate, calcium, and PTH levels regularly, aiming for phosphate levels of 2.5-4.5 mg/dL, as high phosphate concentrations are linked to mortality among patients with CKD stage G3a to G5 and transplant recipients 1. It is essential to individualize phosphate-lowering treatment decisions, considering the potential harm of liberal calcium exposure in normophosphatemic adults with CKD stage G3b or G4, and the lack of data from clinical trials showing that therapeutic approaches to decreasing serum phosphate levels improve patient-centered outcomes 1.

From the FDA Drug Label

The ability of sevelamer hydrochloride to lower serum phosphorus in CKD patients on dialysis was demonstrated in six clinical trials: one double-blind placebo-controlled 2-week study (sevelamer hydrochloride N=24); two open-label uncontrolled 8-week studies (sevelamer hydrochloride N=220) and three active-controlled open-label studies with treatment durations of 8 to 52 weeks (sevelamer hydrochloride N=256). Eighty-four CKD patients on hemodialysis who were hyperphosphatemic (serum phosphorus >6 mg/dL) following a two-week phosphate binder washout period received sevelamer hydrochloride and active-control for eight weeks each in random order. Both treatments significantly decreased mean serum phosphorus by about 2 mg/dL (Table 5). Average daily sevelamer hydrochloride dose at the end of treatment was 4.9 g (range of 0 to 12.6 g).

To manage a patient with hyperphosphatemia, sevelamer hydrochloride can be used as a treatment option. The recommended dose is not explicitly stated, but the average daily dose in the studies ranged from 4.9 g to 6.5 g. The treatment should be started three times per day with meals, and the dose can be titrated up to control serum phosphorus. Key points to consider:

• Sevelamer hydrochloride has been shown to significantly decrease mean serum phosphorus in patients with hyperphosphatemia.
• The treatment should be individualized and the dose adjusted based on the patient's response.
• The patient should be monitored regularly to assess the effectiveness of the treatment and to make any necessary adjustments to the dose. 2

From the Research

Management of Hyperphosphatemia

The management of hyperphosphatemia involves a multi-faceted approach, including dietary restrictions, phosphate binders, and dialysis.

• Dietary restriction of phosphate intake is the first step in managing hyperphosphatemia, as phosphate overload in the diet can exacerbate the condition 3.
• Phosphate binders, such as calcium-based and non-calcium-based binders, can be used to reduce phosphate levels in the blood 4, 5.
• Dialysis can also be used to remove excess phosphate from the blood, especially in patients with end-stage renal disease 5.
• The use of phosphate education and planning talks can also be effective in improving hyperphosphatemia by encouraging patients to make dietary modifications and use phosphate binders correctly 6.

Phosphate Binders

Phosphate binders are an essential part of hyperphosphatemia management.

• Calcium-based phosphate binders, such as calcium acetate, are effective in controlling serum phosphorus and Ca x P product in hemodialysis patients 4.
• Non-calcium-based phosphate binders, such as sevelamer hydrochloride, can also be used as an alternative to calcium-based binders, especially in patients with cardiovascular calcification 4.
• The choice of phosphate binder depends on the individual patient's needs and medical history 4, 5.

Dietary Management

Dietary management is crucial in controlling hyperphosphatemia.

• Patients with chronic kidney disease should limit their dietary phosphate intake to less than 1.0 g/kg/day 7.
• Protein-rich foods are a major source of dietary phosphorus, and patients should be advised to increase their dietary protein intake while managing their hyperphosphatemia 7.
• Renal care professionals should provide patients with personalized dietary advice and phosphate control plans to help them manage their hyperphosphatemia effectively 7, 6.