What are the recommended management strategies for chronic kidney disease–mineral and bone disorder (CKD-MBD)?

Management of Chronic Kidney Disease–Mineral and Bone Disorder (CKD-MBD)

Base all treatment decisions on serial assessments of phosphate, calcium, and PTH levels considered together, rather than targeting individual parameters in isolation. 1

Core Monitoring Strategy

Serial biochemical monitoring drives treatment decisions:

• Monitor phosphate, calcium, and PTH together at intervals based on CKD stage 1
• In CKD G3a-G5 not on dialysis: evaluate patients with progressively rising or persistently elevated PTH (above upper normal limit) for modifiable factors including hyperphosphatemia, hypocalcemia, high phosphate intake, and vitamin D deficiency 1
• In CKD G5D (dialysis): maintain intact PTH at 2-9 times the upper normal limit of the assay 1

Phosphate Management Algorithm

Lower elevated phosphate levels toward the normal range in all CKD G3a-G5D patients: 1

1. Initiate treatment only for progressively or persistently elevated phosphate (not single measurements) 1

2. First-line interventions:

   • Limit dietary phosphate intake, considering phosphate source (animal, vegetable, additives differ in bioavailability) 1
   • In dialysis patients (G5D), increase dialytic phosphate removal for persistent hyperphosphatemia 1

3. Phosphate binder selection:

   • Restrict the dose of calcium-based phosphate binders in adults receiving phosphate-lowering treatment 1
   • Further restrict calcium-based binders if arterial calcification, adynamic bone disease, or persistently low PTH are present 1
   • Avoid aluminum-containing phosphate binders for long-term use 1

Calcium Management

Avoid hypercalcemia in adults with CKD G3a-G5D: 1

• Maintain serum calcium in age-appropriate normal range for children 1
• Use dialysate calcium concentration between 1.25-1.50 mmol/L (2.5-3.0 mEq/L) in G5D patients 1

PTH Management by CKD Stage

For CKD G3a-G5 (Not on Dialysis):

The optimal PTH level is not known, but act on progressively rising or persistently elevated PTH: 1

1. First correct modifiable factors:

   • Address hyperphosphatemia with dietary restriction and phosphate binders
   • Correct hypocalcemia with calcium supplements
   • Treat vitamin D deficiency with native vitamin D
   • Reduce high phosphate intake 1

2. Avoid routine use of calcitriol and vitamin D analogs 1

   • Reserve calcitriol/vitamin D analogs only for CKD G4-G5 patients with severe and progressive hyperparathyroidism despite correction of modifiable factors 1

For CKD G5D (Dialysis):

Target PTH range of 2-9 times upper normal limit: 1

For PTH-lowering therapy, use calcimimetics, calcitriol, vitamin D analogs, or combination therapy: 1

• All options are acceptable first-line choices 1
• Reduce or stop calcitriol/vitamin D analogs if hypercalcemia or hyperphosphatemia develops 1
• Reduce or stop calcimimetics if hypocalcemia develops (based on severity and symptoms) 1
• Reduce or stop all PTH-lowering agents if PTH falls below 2 times upper normal limit 1

Consider parathyroidectomy for severe hyperparathyroidism failing medical/pharmacological therapy 1

Bone Disease Assessment and Fracture Risk

Perform BMD testing in CKD G3a-G5D patients with evidence of CKD-MBD and/or osteoporosis risk factors if results will impact treatment decisions: 1

• This represents a major shift from 2009 guidelines, as multiple prospective studies now demonstrate that lower BMD predicts fractures in CKD patients 1

Use PTH or bone-specific alkaline phosphatase to evaluate bone turnover, as markedly high or low values predict underlying bone disease: 1

Consider bone biopsy if knowledge of renal osteodystrophy type will impact treatment decisions 1

Cardiovascular Calcification Risk

Identify patients with vascular or valvular calcification as highest cardiovascular risk: 1

• Use lateral abdominal radiograph for vascular calcification or echocardiogram for valvular calcification as alternatives to CT-based imaging 1
• Use this information to guide more aggressive CKD-MBD management 1

Osteoporosis Treatment in CKD

For CKD G1-G2 with osteoporosis/high fracture risk: manage as general population 1

For CKD G3a-G3b with normal PTH and osteoporosis/high fracture risk: treat as general population 1

For CKD G3a-G5D with biochemical CKD-MBD abnormalities plus low BMD/fragility fractures: 1

• Treatment choices must account for magnitude and reversibility of biochemical abnormalities and CKD progression
• Consider bone biopsy before antiresorptive therapy 1

Critical Pitfalls to Avoid

• Never target single biochemical parameters in isolation—always consider phosphate, calcium, and PTH together 1
• Do not routinely use calcitriol/vitamin D analogs in non-dialysis CKD—reserve for severe, progressive hyperparathyroidism in G4-G5 only 1
• Avoid excessive calcium-based phosphate binders—particularly with arterial calcification, adynamic bone disease, or low PTH 1
• Do not treat based on single elevated phosphate measurements—require progressive or persistent elevation 1
• Recognize that BMD now predicts fractures in CKD—unlike older 2009 guidance that discouraged routine BMD testing 1