What is the treatment for secondary hyperparathyroidism?

Treatment of Secondary Hyperparathyroidism

The treatment of secondary hyperparathyroidism (SHPT) should begin with phosphate control, vitamin D supplementation, and calcimimetics, with parathyroidectomy reserved for cases refractory to medical therapy. 1

Diagnosis and Assessment

• Monitor serum calcium, phosphorus, and PTH levels regularly
• Target iPTH levels vary by CKD stage:
  • CKD G3: <70 pg/mL
  • CKD G4: <110 pg/mL
  • CKD G5: <300 pg/mL
  • CKD G5D (dialysis): 150-600 pg/mL 1
• Measure alkaline phosphatase (ALP) as a biomarker of bone turnover
• Assess renal phosphate handling using TmP/GFR when appropriate

Medical Management Algorithm

Step 1: Phosphate Control

• Restrict dietary phosphorus intake to 800-1000 mg/day 1
• Initiate phosphate binders to control serum phosphorus levels
• Monitor serum calcium and phosphorus within 1 week of treatment initiation or dose adjustment 2

Step 2: Vitamin D Therapy

• Correct vitamin D deficiency with nutritional vitamin D (cholecalciferol or ergocalciferol) 1
• For patients with CKD Stage 3-4, consider doxercalciferol which is FDA-approved for SHPT treatment 3
• For more advanced SHPT, use active vitamin D analogs (vitamin D sterols) 1

Step 3: Calcimimetics (for dialysis patients)

• Cinacalcet is indicated for SHPT in adult patients with CKD on dialysis 2
• Starting dose: 30 mg once daily with food
• Titrate dose every 2-4 weeks through sequential doses of 30,60,90,120, and 180 mg once daily
• Target iPTH levels of 150-300 pg/mL
• Monitor serum iPTH 1-4 weeks after initiation or dose adjustment
• Important: Cinacalcet is not indicated for CKD patients not on dialysis due to increased hypocalcemia risk 2

Step 4: Combination Therapy

• Cinacalcet can be used alone or in combination with vitamin D sterols and/or phosphate binders 2
• Adjust therapy based on PTH levels:
  • 150-300 pg/mL: Maintain current therapy
  • 300-500 pg/mL: Increase vitamin D sterols, adjust phosphate binders
  • 500-800 pg/mL: Higher doses of vitamin D sterols, consider adding cinacalcet

  • 800 pg/mL: Consider parathyroidectomy if medical therapy fails 1

Surgical Management

Consider parathyroidectomy when:

• PTH levels persist >800 pg/mL for >6 months despite optimal medical therapy 4
• Concomitant disorders exist: persistent hypercalcemia/hyperphosphatemia, tissue/vascular calcification, calciphylaxis, worsening osteodystrophy 4

Surgical Options:

1. Total Parathyroidectomy (TPTX):

   • Lower recurrence rates (OR = 0.20; 95%CI, 0.11-0.38; P < 0.01)
   • Higher risk of hypoparathyroidism (OR = 2.97; 95%CI, 1.09-8.08; P = 0.01)
   • Shorter operative time 5

2. Total Parathyroidectomy with Autotransplantation (TPTX+AT):

   • Higher recurrence rates
   • Lower risk of permanent hypoparathyroidism 1

Special Considerations

Non-CKD Secondary Hyperparathyroidism

• For SHPT due to insufficient calcium intake with normal kidney function and vitamin D levels:
  • Calcium supplementation (600 mg twice daily) can normalize PTH levels within 2-3 weeks 6

Post-Surgical Monitoring

• Monitor for hungry bone syndrome (occurs in ~25% of dialysis patients after parathyroidectomy)
• Provide high doses of oral and intravenous calcium with calcitriol supplementation if needed 4
• Continue regular monitoring of calcium, phosphorus, and PTH levels

Common Pitfalls to Avoid

1. Hypercalcemia: Monitor calcium levels closely when using vitamin D analogs
2. Inadequate phosphate control: Phosphate control is essential before initiating vitamin D therapy
3. Using cinacalcet in non-dialysis CKD patients: Increased risk of hypocalcemia 2
4. Relying on single PTH measurements: Base treatment decisions on trends rather than single values 1
5. Delayed surgical referral: Consider parathyroidectomy earlier for patients with refractory SHPT
6. Inadequate post-surgical monitoring: Watch for hungry bone syndrome and hypocalcemia

Parathyroidectomy is associated with 15%-57% greater survival in dialysis patients and improves hypercalcemia, hyperphosphatemia, tissue calcification, bone mineral density, and health-related quality of life 4, making it an important consideration for patients with medically refractory SHPT.