What are the KDIGO (Kidney Disease: Improving Global Outcomes) guidelines for treating osteoporosis in patients with chronic kidney disease?

KDIGO Guidelines for Treatment of Osteoporosis in CKD

Treatment of osteoporosis in CKD patients should be stratified by CKD stage and PTH status: patients with CKD G1-G2 and CKD G3a-G3b with normal PTH should be treated as the general population with standard osteoporosis therapies, while those with CKD G3a-G5D with biochemical abnormalities of CKD-MBD require optimization of mineral metabolism before considering bone-targeting drugs, with consideration of bone biopsy to guide therapy. 1

Treatment Algorithm by CKD Stage

CKD G1-G2 (eGFR ≥60 ml/min/1.73 m²)

• Treat exactly as the general population when osteoporosis or high fracture risk is identified by WHO criteria (1A recommendation) 1
• Use standard bisphosphonates, denosumab, or other osteoporosis medications without restriction
• No special CKD-related considerations needed at this stage

CKD G3a-G3b (eGFR 30-59 ml/min/1.73 m²)

• If PTH is in the normal range: Treat as the general population (2B recommendation) 1
• If PTH is elevated or other CKD-MBD abnormalities present: Move to the advanced CKD algorithm below
• This is the critical decision point where CKD-specific factors begin to matter

CKD G3a-G5D (eGFR <60 ml/min/1.73 m² with biochemical abnormalities)

This is where treatment becomes complex and individualized based on bone turnover status:

Step 1: Assess for CKD-MBD Biochemical Abnormalities

Before treating osteoporosis, evaluate and address:

• PTH levels: Target progressively rising or persistently elevated PTH above upper normal limit 1
• Phosphate: Manage hyperphosphatemia with dietary restriction and phosphate binders 1
• Calcium: Avoid hypercalcemia; restrict calcium-based phosphate binders 1
• 25(OH) vitamin D: Correct deficiency using general population strategies 1

Step 2: Consider Bone Biopsy

• Bone biopsy should be considered if knowledge of bone turnover status (high vs. low) will impact treatment decisions (Not Graded) 1
• This is particularly important because:
  • Antiresorptive drugs will worsen low bone turnover states
  • Denosumab can cause severe hypocalcemia in CKD
  • The risk-benefit calculation depends on accurate diagnosis 1

Step 3: Treatment Choices Based on Biochemical Profile

Treatment must account for 1:

• Magnitude of biochemical abnormalities
• Reversibility of these abnormalities
• Rate of CKD progression
• Underlying bone turnover state

Key principle from 2025 KDIGO Controversies Conference: Osteoporosis and renal osteodystrophy (ROD) are no longer considered mutually exclusive—the term "CKD-associated osteoporosis" now encompasses both entities 2

Diagnostic Tools to Guide Treatment

Bone Mineral Density (BMD) Testing

• Perform DXA BMD in CKD G3a-G5D with evidence of CKD-MBD and/or osteoporosis risk factors if results will impact treatment (2B recommendation) 1
• WHO T-scores predict fracture risk similarly in CKD as in general population 2
• BMD can monitor response to therapy 2

Bone Turnover Markers

Use PTH and bone-specific alkaline phosphatase to evaluate bone turnover because markedly high or low values predict underlying bone turnover (2B recommendation) 1

The 2025 KDIGO Controversies Conference emphasized that evaluating multiple biochemical measures together (bone turnover markers + PTH + 25-[OH] vitamin D) is most useful for guiding therapy choices and monitoring response 2

Special Populations

Dialysis Patients (CKD G5D)

• Maintain PTH levels 2-9 times upper normal limit (2C recommendation) 1
• For PTH-lowering: Use calcimimetics, calcitriol, vitamin D analogs, or combinations (2B recommendation) 1
• Consider parathyroidectomy for severe hyperparathyroidism failing medical therapy (2B recommendation) 1

Kidney Transplant Recipients

• First 12 months post-transplant with eGFR >30 ml/min/1.73 m²: Consider vitamin D, calcitriol/alfacalcidol, and/or antiresorptive agents for low BMD (2D recommendation) 1
• Treatment choices should be influenced by presence of CKD-MBD abnormalities (calcium, phosphate, PTH, alkaline phosphatase, 25(OH)D) (2C recommendation) 1
• CKD G4T-G5T: Manage as CKD G4-G5 not on dialysis 1

Critical Pitfalls to Avoid

1. Do not use antiresorptive drugs in low bone turnover states without bone biopsy confirmation—they will worsen the condition 1

2. Denosumab carries significant hypocalcemia risk in advanced CKD—use with extreme caution and close calcium monitoring 1

3. Do not treat osteoporosis in CKD G3a-G5D without first optimizing mineral metabolism—this is the sequential approach supported by current evidence 3

4. Avoid long-term aluminum-containing phosphate binders (1C recommendation) 1

5. Restrict calcium-based phosphate binders in adults receiving phosphate-lowering treatment (2B recommendation) 1

Emerging Concepts from 2025 KDIGO Update

The most recent 2025 KDIGO Controversies Conference introduced important conceptual shifts 2:

• CKD-associated osteoporosis is now the preferred inclusive term that recognizes the global impact of kidney disease on bone strength
• Osteoporosis and ROD are no longer viewed as mutually exclusive diagnoses
• Therapies must be personalized based on bone turnover and mineralization status
• Multiple biochemical measures should guide therapy choices rather than single markers

The bottom line: Treatment requires a sequential approach—optimize mineral metabolism first, then cautiously consider bone-targeting therapies with knowledge of bone turnover status, ideally confirmed by bone biopsy in uncertain cases.