At what level should Parathyroid Hormone (PTH) be treated in patients with renal hyperparathyroidism?

Treatment of PTH in Renal Hyperparathyroidism

In patients with CKD G5D, PTH levels should be maintained in the range of approximately 2 to 9 times the upper normal limit for the assay (approximately 150-600 pg/mL for most assays). 1

PTH Target Levels by CKD Stage

Non-Dialysis CKD (G3a-G5)

• For CKD G3a-G4: Evaluate for modifiable factors when PTH is progressively rising or persistently above the upper normal limit 1
• For CKD G3: Target PTH <70 pg/mL 1
• For CKD G4: Target PTH <110 pg/mL 1
• For CKD G5 (non-dialysis): Target PTH <300 pg/mL 1

Dialysis-Dependent CKD (G5D)

• Target range: 2-9× upper normal limit (approximately 150-600 pg/mL for most assays) 1
• Marked changes in PTH levels in either direction within this range should prompt therapy adjustment 1

Treatment Algorithm Based on PTH Levels

For PTH <100 pg/mL (Adynamic Bone Disease)

• Decrease or eliminate calcium-based phosphate binders 1
• Reduce or discontinue vitamin D therapy 1
• Allow PTH levels to rise to increase bone turnover 1

For PTH 100-300 pg/mL

• Maintain current therapy if stable 2
• Monitor calcium and phosphorus levels every 6-12 months 1

For PTH 300-500 pg/mL

• Increase vitamin D sterols 2
• Adjust phosphate binders (preferably non-calcium based) 1
• Monitor calcium and phosphorus levels closely 1

For PTH 500-800 pg/mL

• Higher doses of vitamin D sterols 2
• Consider adding cinacalcet (starting dose 30 mg daily) 2, 3
• Titrate cinacalcet every 3-4 weeks to maximum 180 mg daily to achieve target PTH 3

For PTH >800 pg/mL

• Consider parathyroidectomy if medical therapy fails 1
• Combination therapy with calcimimetics and vitamin D analogs 1

Medication Management

Calcimimetics (Cinacalcet)

• Starting dose: 30 mg once daily 3
• Titration: Every 3-4 weeks to maximum 180 mg daily 3
• Target: iPTH ≤250 pg/mL 3
• Monitor serum calcium within 1 week after initiation or dose adjustment 2
• Discontinue if serum calcium <7.8 mg/dL or symptoms of hypocalcemia occur 3

Vitamin D Sterols

• Use in CKD G4-G5 with severe and progressive hyperparathyroidism 1
• Avoid routine use in CKD G3a-G5 not on dialysis 1
• May increase serum calcium and phosphorus levels 1

Monitoring Parameters

• Serum calcium and phosphate: At least weekly until stable in post-transplant period 1
• PTH, calcium, phosphate: Every 6-12 months in stable CKD G3a-G3b 1
• More frequent monitoring based on presence and magnitude of abnormalities 1

Important Considerations

Phosphate Control

• Restrict dietary phosphate intake in patients with elevated PTH 1
• Use phosphate binders, preferably limiting calcium-based binders 1
• Target phosphate levels toward the normal range 1

Calcium Management

• Avoid hypercalcemia 1
• Consider dialysate calcium concentration between 1.25 and 1.50 mmol/L 1
• Calcium supplements may be needed if hypocalcemia occurs during calcimimetic therapy 3

Parathyroidectomy Indications

• Persistent serum levels of intact PTH >800 pg/mL 1
• Associated with hypercalcemia and/or hyperphosphatemia refractory to medical therapy 1
• Surgical options: subtotal parathyroidectomy or total parathyroidectomy with autotransplantation 1

Clinical Pitfalls to Avoid

1. Overcorrection of PTH: Excessively low PTH (<100 pg/mL) can lead to adynamic bone disease 1

2. Hypercalcemia: Monitor calcium levels closely when using vitamin D analogs 1

3. Hypocalcemia: Common side effect of calcimimetics, requiring close monitoring 3, 4

4. Gastrointestinal side effects: Nausea and vomiting are common with cinacalcet (RR 2.02 and 1.97 respectively) 4

5. Ignoring trends: Focus on trends in PTH values rather than single measurements 1

6. Neglecting mineral balance: Consider calcium, phosphorus, and PTH together when making treatment decisions 1