Evidence-Based Guidelines for the Diagnosis and Treatment of Pediatric CKD-Mineral and Bone Disorder (2024) — Summary

Issued by: Subspecialty Group of Nephrology, the Society of Pediatrics, Chinese Medical Association Published: 2024 Full title: Evidence-Based Guidelines for the Diagnosis and Treatment of Pediatric CKD-Mineral and Bone Disorder (Version 2024) Abbreviation: Pediatric CKD-MBD

Core statement: Pediatric CKD-MBD is a systemic disorder of mineral and bone metabolism caused by chronic kidney disease, characterized by biochemical abnormalities, bone turnover/mineralization/quality impairment and ectopic calcification. Children differ fundamentally from adults due to active skeletal growth. Management goals are to preserve linear growth, prevent bone pain/fractures, avoid vascular and soft tissue calcification, and maintain age-appropriate serum mineral and PTH levels.

1. Definition and clinical screening

CKD-MBD in children includes three interrelated components:

1. Laboratory abnormalities of calcium, phosphate, PTH, and vitamin D metabolism
2. Bone disease (altered turnover, mineralization, volume, strength)
3. Ectopic soft tissue/vascular calcification

Screening timing:

• CKD G1–G2: baseline serum calcium, phosphate, intact PTH, 25(OH)D; repeat annually
• CKD G3a–G3b: repeat every 6 months
• CKD G4–G5 / dialysis: repeat every 1–3 months
• Growth parameters, height Z-score, bone age, and fracture history are monitored throughout all stages.

Bone biopsy is not routine. It is reserved for complex cases: unexplained multiple fractures, severe bone pain, conflicting biochemistry, suspected adynamic bone disease or osteomalacia.

2. Biochemical target ranges (age-stratified)

1. Serum corrected calcium: maintain within age-matched normal reference range
2. Serum phosphate: maintain within age-appropriate normal range; hyperphosphatemia should be avoided starting from early CKD
3. Intact PTH:
   • CKD G1–G2: keep within normal age range
   • CKD G3a–G3b: upper half of age-normal range
   • CKD G4–G5 non-dialysis: 2–9 × upper limit of normal (ULN)
   • CKD G5D (dialysis): 2–9 × ULN
4. 25-hydroxyvitamin D: target ≥30 ng/mL (75 nmol/L); 20–29 ng/mL = insufficiency; ＜20 ng/mL = deficiency.

3. Nutritional phosphate control

• Dietary phosphate restriction should meet age-appropriate protein/energy needs for growth; do not restrict protein excessively.
• If serum phosphate exceeds target despite dietary adjustment, initiate phosphate binders.
  • Calcium-based binders: use cautiously; avoid total calcium overload, especially if PTH is suppressed or vascular calcification exists.
  • Non-calcium binders (sevelamer): preferred when calcium load must be limited.
• Lanthanum is not recommended for young children due to limited pediatric safety data.

4. Vitamin D therapy

1. Native vitamin D (cholecalciferol / ergocalciferol) is used to treat vitamin D insufficiency/deficiency in all CKD stages.
2. Active vitamin D (calcitriol, alfacalcidol): indicated for secondary hyperparathyroidism (SHPT) in CKD G3b–G5.
   • Start at low dose; monitor calcium and phosphate closely.
   • Hold or reduce dose if hypercalcemia or hyperphosphatemia develops.
3. Active vitamin D should not be used solely to correct low 25(OH)D.

5. Calcimimetic (cinacalcet)

• Indication: CKD G5D children with persistent SHPT, when active vitamin D cannot be used or fails, and hypercalcemia is present.
• Starting dose: 0.2 mg/kg per day (≥6 years old); titrate every 4 weeks.
• Major risk: hypocalcemia; serum calcium must be checked within 1 week after initiation or dose increase.
• Not recommended as first-line for non-dialysis CKD children.

6. Management of adynamic bone disease

• Suppressed PTH below target range: reduce/stop active vitamin D and calcium-containing binders.
• Avoid over-suppression of PTH, which increases fracture risk and impairs growth.

7. Ectopic calcification

• Avoid sustained hypercalcemia, hyperphosphatemia and elevated calcium-phosphate product.
• Vascular/soft tissue calcification imaging is not routine; consider in patients with persistently high Ca×P product or clinical signs.

8. Growth and bone age

• Linear growth and height Z-score are key outcome markers in pediatric CKD-MBD.
• Bone age radiograph once or twice yearly in progressive CKD.
• Optimize nutrition, anemia control and CKD-MBD before considering growth hormone.

9. Parathyroidectomy

Indicated for refractory severe SHPT: persistently very high PTH, refractory hypercalcemia/hyperphosphatemia, bone pain, fractures, progressive calcification despite maximum medical therapy.

10. Key warnings and common pitfalls

1. Adult PTH targets cannot be directly applied to growing children.
2. Do not over-restrict dietary phosphate at the cost of protein intake and growth.
3. Calcium-based binders may cause calcium overload; monitor total calcium intake (diet + binders).
4. Active vitamin D is not for vitamin D deficiency; native vitamin D is first-line for 25(OH)D insufficiency.
5. Cinacalcet carries hypocalcemia risk; close calcium monitoring is mandatory.
6. Bone biopsy is not required before starting medical therapy; reserved for complex diagnostic uncertainty.

11. Summary takeaway

This guideline emphasizes growth-centered, age-stratified targets for pediatric CKD-MBD. Management is staged: nutritional phosphate control, native vitamin D repletion, active vitamin D for SHPT, and non-calcium binders/cinacalcet for selected dialysis patients. The primary goals are normal mineral homeostasis, preservation of linear growth, and prevention of fractures and ectopic calcification. PTH targets differ across CKD stages, and overtreatment leading to adynamic bone disease must be avoided.