Management of Severe Hyperphosphatemia and Hyperparathyroidism in Dialysis

Introduction to Management

• The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines recommend controlling phosphorus levels in dialysis patients, with a target range of 3.5-5.5 mg/dL 1
• The K/DOQI guidelines also recommend controlling PTH levels in dialysis patients, with a target range of 150-300 pg/mL 2

Phosphate Binder Management

• The K/DOQI guidelines explicitly recommend combination therapy when hyperphosphatemia persists despite single-agent phosphate binders 1
• Sevelamer effectively lowers phosphorus without increasing calcium load, making it ideal for patients with borderline-high calcium 1
• The American Journal of Kidney Diseases recommends escalating sevelamer aggressively to 1600 mg three times daily with meals (4.8 g/day), with a plan to titrate up to 2400 mg three times daily (7.2 g/day) within 2-4 weeks if phosphorus remains >5.5 mg/dL 1

Vitamin D Sterol Management

• The K/DOQI guidelines state that dialysis patients with PTH >300 pg/mL should receive active vitamin D sterols to reduce PTH to 150-300 pg/mL 2
• Intravenous calcitriol is more effective than oral administration for lowering PTH in hemodialysis patients 2
• The American Journal of Kidney Diseases recommends increasing calcitriol to 1.0 mcg intravenously three times weekly after dialysis sessions 2

Monitoring Protocol

• The K/DOQI guidelines require measuring calcium and phosphorus every 2 weeks for the first month, then monthly thereafter 2
• The American Journal of Kidney Diseases recommends measuring PTH monthly for at least 3 months, then every 3 months once target levels are achieved 2

Dose Adjustment Algorithm

• If phosphorus remains >5.5 mg/dL after 2-4 weeks, the American Journal of Kidney Diseases recommends increasing sevelamer by 800 mg per meal (2.4 g/day increment) every 2-4 weeks until phosphorus reaches target 1
• If calcium rises above 9.5 mg/dL, the American Journal of Kidney Diseases recommends holding calcitriol immediately until calcium returns to <9.5 mg/dL, then resuming at 0.5 mcg IV three times weekly (half the previous dose) 2
• If PTH falls below 150 pg/mL, the American Journal of Kidney Diseases recommends holding calcitriol until PTH rises above 150 pg/mL, then resuming at 0.5 mcg IV three times weekly (half the previous dose) 2