CKD-Mineral Bone Disease (CKD-MBD)

Last updated 31 May 2026 · Renal & nephrology guideline

📋 Key Information Summary

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CKD-MBD is a systemic disorder encompassing biochemical abnormalities (elevated PTH, hyperphosphataemia, hypocalcaemia, raised FGF-23), bone abnormalities (renal osteodystrophy), and vascular/soft-tissue calcification.
FGF-23 is the earliest biomarker to rise (CKD 2–3), preceding phosphate and PTH elevations by months to years.
Phosphate targets: serum phosphate maintained within the age-appropriate reference range; target 0.8–1.5 mmol/L in adults on dialysis.
PTH targets in dialysis: 2–9× the upper limit of normal for intact PTH assay; trends matter more than individual values.
Corrected calcium should be maintained within the normal reference range (2.10–2.55 mmol/L); avoid hypercalcaemia and adynamic bone disease.
Renal osteodystrophy has two major subtypes: high-turnover (osteitis fibrosa, secondary hyperparathyroidism) and low-turnover (adynamic bone disease, osteomalacia).
Phosphate binders are first-line for hyperphosphataemia: sevelamer or lanthanum preferred over calcium-based binders to reduce vascular calcification risk.
Calcitriol (1,25-dihydroxyvitamin D) or alfacalcidol is used to suppress secondary hyperparathyroidism; native vitamin D (cholecalciferol) should be supplemented in all CKD patients with insufficiency.
Cinacalcet is PBS Authority Required for dialysis patients with secondary hyperparathyroidism uncontrolled despite phosphate binders and vitamin D therapy.
Vascular calcification screening (lateral abdominal X-ray or CT) should be considered in CKD 4–5 as it independently predicts cardiovascular mortality.
Aboriginal and Torres Strait Islander peoples have higher CKD prevalence, younger age at dialysis commencement, and reduced access to specialist nephrology services — CKD-MBD screening must begin earlier.
Parathyroidectomy is reserved for refractory tertiary hyperparathyroidism or severe symptomatic disease; subtotal or total with auto-transplant is standard.

Introduction & Australian Epidemiology

Chronic Kidney Disease–Mineral and Bone Disorder (CKD-MBD) is a systemic disorder of mineral and bone metabolism that occurs in progressive chronic kidney disease. It encompasses three interrelated components: biochemical abnormalities (elevated PTH, hyperphosphataemia, hypocalcaemia, and raised FGF-23), bone abnormalities collectively termed renal osteodystrophy, and vascular or soft-tissue calcification. CKD-MBD is a major driver of morbidity and mortality in patients with CKD stages 3–5 and those receiving dialysis, primarily through accelerated cardiovascular disease and fracture risk.

In Australia, CKD-MBD affects the majority of patients on maintenance dialysis. Data from the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry indicate that approximately 50–60% of prevalent haemodialysis patients have elevated serum phosphate, and over 80% exhibit elevated intact PTH levels. Vascular calcification is detectable in up to 80% of patients commencing dialysis. The disease burden is disproportionately borne by Aboriginal and Torres Strait Islander peoples, who develop end-stage kidney disease at rates 6–8 times higher than non-Indigenous Australians and often present with more severe mineral bone disease at younger ages.

The economic burden of CKD-MBD is significant. Phosphate binders, active vitamin D analogues, and calcimimetics represent substantial pharmaceutical expenditure through the Pharmaceutical Benefits Scheme (PBS), while vascular calcification-related cardiovascular events contribute to hospitalisation costs estimated at over

.5 billion annually for CKD care in Australia.

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Clinical significance: CKD-MBD is not merely a biochemical curiosity — hyperphosphataemia and elevated PTH independently predict all-cause and cardiovascular mortality in dialysis patients. Early recognition and management from CKD stage 3 can alter disease trajectory.

CKD-Mineral Bone Disease (CKD-MBD) clinical infographic — pathophysiology, clinical clues, diagnosis, imaging, and management — Tap or click image to enlarge — CKD-Mineral Bone Disease (CKD-MBD): pathophysiology, clinical clues, diagnosis, imaging, and management.

Pathophysiology — FGF-23, PTH, and Vitamin D

The pathophysiology of CKD-MBD involves a cascade of endocrine and paracrine disturbances that begin early in CKD and progress with declining nephron mass. Three key hormonal axes are central: fibroblast growth factor 23 (FGF-23), parathyroid hormone (PTH), and the vitamin D axis.

FGF-23 — The Earliest Abnormality

FGF-23, a phosphaturic hormone secreted by osteocytes, is the earliest detectable abnormality in CKD-MBD, rising from CKD stage 2–3 — well before serum phosphate becomes elevated. FGF-23 acts on the proximal tubule to promote urinary phosphate excretion and suppresses 1α-hydroxylase activity, reducing calcitriol (1,25-dihydroxyvitamin D) production. As nephron mass declines, the compensatory rise in FGF-23 becomes insufficient to maintain phosphate homeostasis, leading to positive phosphate balance and subsequent PTH elevation.

Elevated FGF-23 is independently associated with left ventricular hypertrophy, cardiovascular events, and all-cause mortality in CKD. It is not yet routinely measured in Australian clinical practice but is an important biomarker in research and increasingly in specialist nephrology assessment.

Parathyroid Hormone (PTH) — Secondary Hyperparathyroidism

Secondary hyperparathyroidism develops through several mechanisms:

Phosphate retention: Directly stimulates PTH secretion and reduces ionised calcium.
Calcitriol deficiency: Reduced vitamin D receptor (VDR) activation on parathyroid glands decreases PTH gene suppression and reduces intestinal calcium absorption.
Hypocalcaemia: Stimulates PTH release via the calcium-sensing receptor (CaSR) on chief cells.
FGF-23 effects: FGF-23 directly acts on parathyroid glands to suppress PTH secretion (via FGFR/Klotho), but parathyroid resistance develops over time.
Parathyroid gland hyperplasia: Chronic stimulation leads to nodular hyperplasia, eventually causing autonomous (tertiary) hyperparathyroidism with reduced response to medical therapy.

PTH acts on bone to increase osteoblast activity and bone turnover. Chronically elevated PTH leads to high-turnover bone disease (osteitis fibrosa cystica), cortical bone loss, and fracture risk. PTH also contributes to vascular calcification indirectly through increased bone resorption and calcium/phosphate release.

Vitamin D Axis

Two vitamin D derangements occur in CKD:

Native vitamin D (25-hydroxyvitamin D) deficiency: Present in 60–80% of CKD patients due to reduced sun exposure, proteinuria (vitamin D binding protein loss), reduced skin synthesis, and dietary restriction. Cholecalciferol supplementation is recommended for all CKD patients with levels <75 nmol/L.
Calcitriol (1,25-dihydroxyvitamin D) deficiency: Results from reduced 1α-hydroxylase activity in the failing kidney and FGF-23-mediated suppression. This is the key driver of secondary hyperparathyroidism and is treated with active vitamin D analogues (calcitriol or alfacalcidol).

The interplay of these three axes creates a vicious cycle: FGF-23 rises → calcitriol falls → PTH rises → phosphate remains elevated → parathyroid hyperplasia → autonomous secretion. Breaking this cycle at multiple points is the therapeutic goal.

Vascular Calcification

CKD-MBD promotes vascular calcification through both passive (metastatic) deposition of calcium-phosphate in the media and intima, and active processes including transformation of vascular smooth muscle cells to an osteoblast-like phenotype. Elevated calcium × phosphate product, hyperphosphataemia, and calcium overload from calcium-based phosphate binders are key drivers. Calcification inhibitors — fetuin-A, matrix Gla protein, and pyrophosphate — are reduced in CKD. Medial calcification increases arterial stiffness and pulse pressure, contributing to the disproportionately high cardiovascular mortality in CKD.

Renal Osteodystrophy Types

Renal osteodystrophy (ROD) is the bone component of CKD-MBD. Histological classification requires bone biopsy (gold standard), though in practice, biochemical markers and imaging are used for diagnosis. The Kidney Disease: Improving Global Outcomes (KDIGO) classification uses the TMV system (Turnover, Mineralisation, Volume).

High Turnover

Osteitis Fibrosa Cystica

Driven by markedly elevated PTH. Characterised by increased osteoclast and osteoblast activity, peritrabecular fibrosis, brown tumours, and subperiosteal erosions. Cortical bone preferentially lost, increasing fracture risk. Bone pain, fractures, and tumour-like lesions may occur.

Biochemistry: PTH markedly elevated (>9× ULN), phosphate elevated, alkaline phosphatase elevated

Low Turnover

Adynamic Bone Disease (ABD)

Now the most common histological finding in Australian dialysis patients (up to 50%). Characterised by reduced osteoblast and osteoclast activity, absence of bone remodelling. Driven by over-suppression of PTH (excessive vitamin D or calcimimetics), diabetes, ageing, or aluminium exposure. High fracture risk despite normal or low PTH. Associated with increased vascular calcification due to reduced bone buffering of calcium and phosphate.

Biochemistry: PTH low-normal or suppressed, calcium often elevated, alkaline phosphatase normal

Low Turnover

Osteomalacia

Defective bone mineralisation with accumulation of unmineralised osteoid. Historically caused by aluminium toxicity (from aluminium-based phosphate binders or dialysate contamination) — now rare in Australia. Can also result from severe vitamin D deficiency. Bone pain, proximal myopathy, fractures. Distinguished from ABD by bone biopsy showing thickened osteoid seams.

Biochemistry: PTH variable, calcium low, phosphate low, vitamin D very low, alkaline phosphatase elevated

Mixed

Mixed Uraemic Osteodystrophy

Features of both high turnover (from secondary hyperparathyroidism) and defective mineralisation (from vitamin D deficiency or aluminium). Bone biopsy shows increased osteoid volume with increased remodelling. Less common with modern aluminium-free practice.

Biochemistry: PTH elevated, vitamin D low, variable calcium and phosphate

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Clinical pitfall: Adynamic bone disease cannot be distinguished from osteitis fibrosa by biochemistry alone — a low PTH in a dialysis patient does not necessarily mean "well-controlled" secondary hyperparathyroidism; it may indicate adynamic bone with high fracture and calcification risk. Bone biopsy remains the only definitive diagnostic tool.

Fracture Risk in CKD-MBD

Fracture rates in CKD stages 4–5 and dialysis patients are 2–4 times higher than age-matched populations. Hip fractures carry a 1-year mortality of 30–40% in dialysis patients. Both high-turnover and low-turnover disease increase fracture risk through different mechanisms: cortical porosity (osteitis fibrosa) and reduced bone formation (ABD). Standard DXA BMD has limited predictive value in CKD 5D due to concurrent cortical and trabecular abnormalities and vascular calcification artefact.

Investigations & Targets

Biochemical monitoring of CKD-MBD should commence from CKD stage 3 and be performed at increasing frequency with advancing CKD stage. The following investigations are recommended:

Essential

Serum Calcium (Corrected for Albumin)

Corrected calcium = measured Ca + 0.02 × (40 − albumin g/L). Target: 2.10–2.55 mmol/L. Monitor every 1–3 months from CKD 4. MBS Item 66500 (calcium).

Essential

Serum Phosphate

Target: 0.8–1.5 mmol/L in CKD 5D (dialysis); maintain within age-appropriate reference range in CKD 3–4. Monitor every 1–3 months from CKD 4. MBS Item 66515.

Essential

Intact PTH (iPTH)

Target in CKD 5D: 2–9× the assay upper limit of normal (typically 16–72 pmol/L or ~150–600 pg/mL depending on assay). In CKD 3–4, maintain within normal range. Trends more important than single values. MBS Item 66833.

Essential

25-Hydroxyvitamin D [25(OH)D]

Target: ≥75 nmol/L. Deficiency (<50 nmol/L) or insufficiency (50–75 nmol/L) should be corrected with cholecalciferol. MBS Item 66836.

Available

Alkaline Phosphatase (ALP)

Bone-specific ALP (if available) is a marker of bone turnover. Elevated ALP supports high-turnover disease. Trends can guide therapy intensity. MBS Item 66510.

Available

Calcium × Phosphate Product

Calculated from corrected calcium and phosphate. Target <4.4 mmol²/L² (55 mg²/dL²). Higher values associated with vascular calcification and mortality.

Specialist

FGF-23

C-terminal or intact FGF-23 assay. Not yet routine in Australian clinical practice; available at major teaching hospital laboratories. Rising FGF-23 is an independent predictor of CKD progression and mortality. Primarily a research and specialist tool.

Specialist

Bone Biopsy (Iliac Crest)

Gold standard for renal osteodystrophy diagnosis. Indicated when biochemical assessment is inconclusive, fracture risk is high, or ABD is suspected. Requires tetracycline double-labelling. Available at major renal centres. Classified by TMV system.

Available

Lateral Abdominal X-ray (for Vascular Calcification)

Can detect abdominal aortic calcification as a surrogate for systemic vascular calcification. Simple, low-cost screening tool. Consider in CKD 4–5 and all dialysis patients. No specific MBS item; billed under standard abdominal X-ray (MBS Item 58503).

Specialist

CT (Vascular Calcification Scoring)

Coronary artery calcium (CAC) scoring or abdominal CT for quantification. More sensitive than plain X-ray. Specialist centres only. Not routinely MBS-reimbursed for CKD-MBD indication.

Monitoring Frequency by CKD Stage

CKD Stage	eGFR (mL/min/1.73 m²)	Frequency	Tests
Stage 2–3a	45–89	Every 6–12 months	Calcium, phosphate, PTH, 25(OH)D
Stage 3b	30–44	Every 3–6 months	Calcium, phosphate, PTH, 25(OH)D, ALP
Stage 4	15–29	Every 1–3 months	Calcium, phosphate, PTH, 25(OH)D, ALP
Stage 5 / 5D	<15 / Dialysis	Monthly (or per dialysis unit protocol)	Calcium, phosphate, PTH, 25(OH)D, ALP

Biochemical Targets Summary

Parameter	CKD 3–4 Target	CKD 5D Target
Corrected Calcium	2.10–2.55 mmol/L (normal range)	2.10–2.55 mmol/L (normal range)
Phosphate	Within normal range (0.8–1.5 mmol/L)	0.8–1.5 mmol/L
Intact PTH	Within normal range (1.6–7.2 pmol/L)	2–9× ULN (~16–72 pmol/L)*
25(OH) Vitamin D	≥75 nmol/L	≥75 nmol/L
Ca × P product	Minimise	<4.4 mmol²/L²

*Assay-specific; consult local laboratory reference ranges. Avoid over-suppression of PTH below 2× ULN in CKD 5D due to adynamic bone disease risk.

Management — Phosphate Binders, Vitamin D, Cinacalcet

Management of CKD-MBD is guided by biochemical targets and involves a stepped approach: dietary phosphate restriction, phosphate binders, vitamin D supplementation, active vitamin D analogues, calcimimetics, and in refractory cases, parathyroidectomy.

Dietary Phosphate Restriction

Dietary phosphate intake should be limited to 800–1000 mg/day (25–32 mmol/day). Patients should be counselled to avoid phosphate-containing food additives (processed meats, soft drinks, preservatives) as inorganic phosphate additives are nearly 100% absorbed compared with 40–60% absorption from organic (food-bound) phosphate. A renal dietitian referral is recommended for all patients with CKD 4–5.

Phosphate Binders

Phosphate binders are the mainstay of hyperphosphataemia treatment. They must be taken with meals to bind dietary phosphate in the gut. Choice depends on calcium status, cost, tolerability, and vascular calcification risk.

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Sevelamer Carbonate

Renvela® · Non-calcium, non-aluminium phosphate binder

Adult dose 800 mg–1600 mg PO TDS with meals; titrate every 2–4 weeks. Typical maintenance 2400–4800 mg/day in divided doses

Paediatric dose ≥6 years: weight-based dosing, start 2.4 g/m²/day in divided doses with meals

Renal adjustment No adjustment needed — acts in gut lumen

Key notes Preferred over calcium-based binders in patients with vascular calcification, adynamic bone disease, or hypercalcaemia. May reduce LDL cholesterol. GI side effects (bloating, nausea) common. Large tablet burden. Avoid if bowel obstruction.

PBS status ⚡ PBS Authority Required

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Lanthanum Carbonate

Fosrenol® · Non-calcium phosphate binder (lanthanum salt)

Adult dose 750 mg–3000 mg/day PO in divided doses with meals. Chew or crush tablets. Start 750 mg/day, titrate every 2–3 weeks

Paediatric dose Not established; limited data in children <18 years

Renal adjustment No adjustment needed

Key notes Lower tablet burden than sevelamer. Chewable tablet may improve adherence. Minimal systemic absorption. Theoretical concerns about lanthanum tissue accumulation (bone, liver) — no clinical harm demonstrated to date.

PBS status ⚡ PBS Authority Required

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Calcium Acetate

PhosLo® · Calcium-based phosphate binder

Adult dose 667 mg (166 mg Ca²⁺) PO TDS with meals; usual range 4–12 tablets/day

Paediatric dose Limited data; specialist supervision required

Key notes Cheapest option but contributes to calcium load. Avoid if corrected calcium >2.55 mmol/L, vascular calcification present, or adynamic bone disease suspected. Total elemental calcium intake (binder + diet) should not exceed 1500 mg/day.

PBS status ✔ PBS General Benefit

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Sucroferric Oxyhydroxide

Velphoro® · Iron-based phosphate binder

Adult dose 500 mg PO TDS with meals (chew, do not swallow whole). Titrate up to 1500 mg TDS. Usual range 1500–3000 mg/day

Key notes Non-calcium, non-aluminium binder with very low iron absorption. Discolours stools (black). Useful adjunct in iron-replete patients. GI side effects (diarrhoea, discoloured teeth).

PBS status ✖ Not PBS

Vitamin D Therapy

Vitamin D therapy in CKD-MBD addresses two separate deficits:

Native Vitamin D Replacement

Cholecalciferol (vitamin D₃) or ergocalciferol (vitamin D₂) should be given to all CKD patients with 25(OH)D <75 nmol/L.

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Cholecalciferol

Ostelin® · Various generics · Vitamin D₃

Adult dose Deficiency (<50 nmol/L): 3000–5000 IU PO daily × 6–8 weeks then maintenance 1000–2000 IU daily. Insufficiency (50–75 nmol/L): 1000–2000 IU PO daily

Paediatric dose 400–1000 IU PO daily depending on age and weight

Key notes Repletes 25(OH)D substrate. Does NOT significantly raise calcitriol in CKD 4–5. Safe in CKD — does not directly raise calcium or phosphate. Monitor 25(OH)D at 3 months then every 6–12 months. Over-the-counter; also PBS-listed as part of combination products.

PBS status ✔ PBS General Benefit (some preparations)

Active Vitamin D Analogues

Active vitamin D analogues directly suppress PTH synthesis and are indicated when PTH is above target despite normalisation of phosphate and 25(OH)D.

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Calcitriol (1,25-Dihydroxyvitamin D₃)

Rocaltrol® · Calcitriol generics

Adult dose 0.25 mcg PO daily initially; titrate every 4–8 weeks. Usual range 0.25–1 mcg PO daily. IV dosing (dialysis): 0.5–1 mcg IV post-dialysis 3×/week

Paediatric dose 10–15 ng/kg/day PO (0.025–0.04 mcg/kg/day)

Key notes Most widely used active vitamin D analogue. Increases intestinal calcium and phosphate absorption — monitor closely. Preferred when PTH moderately elevated. Oral or IV formulations available.

PBS status ✔ PBS General Benefit

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Alfacalcidol (1α-Hydroxyvitamin D₃)

One-Alpha® · Alfacalcidol generics

Adult dose 0.25 mcg PO daily initially; titrate every 2–4 weeks. Usual range 0.25–1 mcg PO daily

Key notes Pro-drug requiring only 25-hydroxylation in the liver (preserved in CKD). Equivalent efficacy to calcitriol. May have slightly less hypercalcaemia risk. Oral only in Australia.

PBS status ✔ PBS General Benefit

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Paricalcitol

Zemplar® · Selective vitamin D receptor activator

Adult dose IV: 0.04–0.1 mcg/kg post-dialysis 3×/week. PO: 1 mcg daily or 2 mcg thrice weekly

Key notes Selective VDRA with less hypercalcaemia and hyperphosphataemia than calcitriol. Preferred in patients with recurrent hypercalcaemia on calcitriol. Limited availability in Australia.

PBS status ✖ Not PBS

Calcimimetics — Cinacalcet

Cinacalcet is a calcimimetic agent that allosterically activates the calcium-sensing receptor (CaSR) on parathyroid chief cells, increasing sensitivity to extracellular calcium and suppressing PTH secretion. It is indicated for secondary hyperparathyroidism in CKD 5D when PTH remains above target despite adequate phosphate binders and active vitamin D therapy.

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Cinacalcet

Mimpara® · Calcimimetic

Adult dose 30 mg PO daily with food or after food. Titrate every 4 weeks: 30 → 60 → 90 → 180 mg/day. Maximum 180 mg/day

Paediatric dose ≥6 years: start at 0.2 mg/kg/day PO (minimum 30 mg), titrate every 4 weeks to max 2.5 mg/kg/day or 180 mg/day (whichever is lower)

Renal adjustment No dose adjustment; titrate based on PTH and calcium response

Key side effects Nausea, vomiting (most common — 30%). Hypocalcaemia — monitor corrected calcium within 1 week of initiation and after each dose increase. Seizure threshold may be lowered (hypocalcaemia).

Monitoring Corrected calcium at 1 week, then every 1–2 weeks until stable. PTH at 4 weeks, then every 1–3 months. Withhold if corrected calcium <2.10 mmol/L.

PBS status ⚡ PBS Authority Required

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Cinacalcet PBS restriction (Australia): Authority Required for treatment of secondary hyperparathyroidism in patients with CKD stage 5D on dialysis, where PTH levels remain above the target range (2–9× ULN) despite at least 3 months of adequate phosphate control and vitamin D therapy. The patient must have a baseline iPTH >9× ULN before initiation, OR iPTH between 2–9× ULN with progressive rise despite optimised therapy. Prescriber must be a nephrologist or have specialist endorsement.

Stepwise Management Algorithm

Correct 25(OH)D Deficiency

Cholecalciferol to maintain 25(OH)D ≥75 nmol/L in all CKD patients. First step before considering active vitamin D or calcimimetics.

Control Phosphate

Dietary restriction (800–1000 mg/day). Add phosphate binder — sevelamer or lanthanum preferred (especially with vascular calcification). Titrate to target phosphate 0.8–1.5 mmol/L.

Treat Secondary Hyperparathyroidism

If PTH above target: initiate calcitriol 0.25 mcg daily (or alfacalcidol). Titrate every 4–8 weeks. Monitor calcium and phosphate for hypercalcaemia and hyperphosphataemia.

Add Cinacalcet if Refractory

If PTH remains above 9× ULN despite phosphate control and adequate vitamin D therapy for ≥3 months. Start cinacalcet 30 mg daily; titrate every 4 weeks. Monitor calcium closely.

Consider Parathyroidectomy

For refractory tertiary hyperparathyroidism (autonomously elevated PTH with hypercalcaemia), severe symptoms (bone pain, fractures, calciphylaxis), or failed medical therapy. Subtotal or total parathyroidectomy with autotransplant. Pre-operative localisation with sestamibi scan or ultrasound.

Calciphylaxis (Calcific Uremic Arteriolopathy)

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Calciphylaxis is a rare but life-threatening complication of CKD-MBD (mortality 50–80%). Characterised by small-vessel calcification leading to ischaemic skin necrosis, typically in areas of adiposity (thighs, abdomen). Risk factors: obesity, warfarin use, hypercalcaemia, calcium-based phosphate binders, hyperparathyroidism, diabetes. Management: urgent sodium thiosulphate (IV 25 g in 100 mL NaCl post-dialysis 3×/week — not PBS-listed), cinacalcet, wound care, stop calcium-based binders and warfarin. Multidisciplinary team including nephrology, dermatology, wound care, and pain management.

Clinical Presentation & Diagnostic Criteria

CKD-MBD is typically identified through biochemical screening in patients with known CKD. Many patients are asymptomatic until advanced disease manifests with skeletal or cardiovascular complications.

Symptoms and Signs

Skeletal Manifestations

Bone pain (especially spine, hips, ribs)
Proximal myopathy
Pathological fractures
Joint swelling (gouty-like in brown tumours)
Brown tumours (cystic bone lesions in osteitis fibrosa)
Subperiosteal erosions (radial side of middle phalanges)

Extra-Skeletal Manifestations

Vascular calcification (coronary, peripheral)
Calciphylaxis (skin necrosis)
Soft-tissue and periarticular calcification
Corneal calcification
Cardiovascular events (MI, stroke, heart failure)
Metastatic calcification in viscera

Diagnostic Criteria (KDIGO 2017)

CKD-MBD is diagnosed when one or more of the following are present in a patient with CKD:

Abnormalities of calcium, phosphate, PTH, or vitamin D metabolism
Abnormalities in bone turnover, mineralisation, volume, linear growth, or strength (renal osteodystrophy)
Vascular or other soft-tissue calcification

No single biochemical value establishes the diagnosis — a combination of serial measurements and trend analysis is required. Bone biopsy is the definitive test for renal osteodystrophy but is not required in routine clinical practice.

Risk Stratification & Severity Scoring

Risk in CKD-MBD is determined by the degree of biochemical derangement, presence of vascular calcification, bone disease type, and comorbid burden.

Low Risk

Early CKD-MBD

CKD 3 with mildly elevated PTH, normal calcium and phosphate, 25(OH)D replete. No vascular calcification. No symptoms.

Management: Monitor every 6–12 months, dietary counselling, cholecalciferol if deficient

Moderate Risk

Established CKD-MBD

CKD 4–5 with PTH above target, mild hyperphosphataemia, mild hypocalcaemia. No symptoms. May have early vascular calcification.

Management: Phosphate binder, active vitamin D, monitor every 1–3 months

High Risk

Advanced CKD-MBD

CKD 5D with markedly elevated PTH (>9× ULN), severe hyperphosphataemia, calciphylaxis, pathological fractures, significant vascular calcification, or tertiary hyperparathyroidism with hypercalcaemia.

Management: Cinacalcet ± reduced active vitamin D, optimise phosphate binders, consider parathyroidectomy, specialist nephrology care

Monitoring

Ongoing monitoring is essential to guide therapy titration and detect complications. Key principles:

Trend analysis over single values: PTH varies significantly between measurements; 3 consecutive values trending in the same direction are more informative than a single result.
Adjust therapy based on trends, not isolated results.
Monitor calcium and phosphate before and after every active vitamin D or cinacalcet dose change.
25(OH)D: Check at 3 months after initiating cholecalciferol, then every 6–12 months.
Alkaline phosphatase: Track every 3–6 months; rising ALP suggests increasing bone turnover.
Vascular calcification: Consider lateral abdominal X-ray at baseline in CKD 5/5D and repeat every 2–3 years or if clinical change.

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Treatment thresholds (KDIGO): Initiate or modify therapy based on trends rather than single thresholds. Start evaluating when PTH progressively rises above the normal range in CKD 3–5 (non-dialysis). In CKD 5D, PTH above or below 2–9× ULN should prompt treatment adjustment. Avoid aggressive PTH suppression below 2× ULN.

Special Populations

🤰 Pregnancy

Active vitamin D: Calcitriol and alfacalcidol are Category B3. Use lowest effective dose. Monitor calcium closely — hypercalcaemia in pregnancy increases risk of neonatal hypercalcaemia and supravalvular aortic stenosis.

Cholecalciferol: Safe in pregnancy. Maintain 25(OH)D ≥75 nmol/L.

Cinacalcet: Category B3 — limited human data. Avoid if possible; discuss with maternal-fetal medicine if essential.

Phosphate binders: Calcium acetate is preferred in pregnancy (longest safety data). Sevelamer is Category B3 (animal data only). Avoid lanthanum (no pregnancy data).

Parathyroidectomy: If required, second trimester is safest. Discuss with surgical and obstetric teams.

👶 Paediatric

Growth failure: CKD-MBD directly impairs linear growth in children. Maintain PTH within normal range (not 2–9× ULN as in adults) to preserve growth plate function.

Phosphate binders: Sevelamer is approved ≥6 years. Calcium acetate used with caution (avoid excessive calcium load). Lanthanum not established in children.

Active vitamin D: Calcitriol 0.025–0.04 mcg/kg/day. Monitor growth velocity and bone age.

Cinacalcet: Approved ≥6 years. Start 0.2 mg/kg/day, titrate carefully. Monitor calcium closely.

Paediatric CKD-MBD monitoring: Include growth charts, bone age X-rays, and nutritional assessment. Refer to paediatric nephrology early.

👴 Elderly (≥65 years)

Adynamic bone disease: Higher prevalence in elderly patients. Avoid over-suppression of PTH with vitamin D or cinacalcet. PTH target may be relaxed.

Fracture risk: CKD-MBD compounds age-related osteoporosis. Fall prevention strategies are essential. DXA interpretation limited in CKD 5D.

Polypharmacy: Phosphate binders add to tablet burden. Consider pill burden when choosing binder (lanthanum may improve adherence with fewer tablets).

Vascular calcification: Nearly universal in elderly dialysis patients. Calcium-based binders should be avoided where possible.

🫘 Renal Impairment (Pre-Dialysis CKD 3–5)

Timing of intervention: Begin CKD-MBD management from CKD stage 3. Phosphate binders typically initiated in CKD 4–5 when hyperphosphataemia develops despite dietary restriction.

CKD 3–4 PTH target: Maintain iPTH within the normal laboratory range (not 2–9× ULN as in dialysis).

Transplant patients: CKD-MBD persists post-transplant. Hyperparathyroidism may persist for months to years. Monitor calcium, phosphate, PTH post-transplant. Cinacalcet can be used post-transplant for persistent hypercalcaemia/hyperparathyroidism.

🫁 Hepatic Impairment

Vitamin D metabolism: Severe liver disease impairs 25-hydroxylation. 25(OH)D levels may be very low; cholecalciferol may be ineffective — consider calcifediol (not available in Australia).

Cinacalcet: Metabolised by CYP3A4; use with caution in severe hepatic impairment (Child-Pugh C). No formal dose adjustment but monitor closely.

Sevelamer: Not absorbed systemically — safe in liver disease.

🛡️ Immunocompromised

Corticosteroid-induced osteoporosis: Contributes to fracture risk in CKD patients on immunosuppression post-transplant. Bisphosphonates are renally cleared — use with caution in CKD 4–5. Denosumab does not require renal dose adjustment but causes hypocalcaemia — monitor closely in CKD.

Post-transplant bone disease: Combination of CKD-MBD, corticosteroid osteoporosis, and calcineurin inhibitor effects. Dual-energy X-ray absorptiometry may be considered in CKD stages 1–3T; not reliable in CKD 4–5T.

Aboriginal and Torres Strait Islander Health Considerations

Aboriginal and Torres Strait Islander Health

Disease Burden

Aboriginal and Torres Strait Islander peoples experience end-stage kidney disease at rates 6–8 times higher than non-Indigenous Australians, with onset at significantly younger ages. CKD-MBD therefore affects a younger population with greater cumulative lifetime exposure to mineral bone disease.

Geographic Access

Many Indigenous Australians live in remote or very remote areas with limited access to nephrology services, dialysis units, and specialist monitoring (iPTH, 25(OH)D). Point-of-care testing for calcium and phosphate may be available through Aboriginal Community Controlled Health Organisations (ACCHOs), but PTH and vitamin D assays often require sample transport to metropolitan laboratories with turnaround times of 5–10 days.

Early Screening

Given the higher prevalence and earlier onset of CKD, CKD-MBD screening (calcium, phosphate, PTH, 25(OH)D) should commence at CKD stage 3 in Indigenous patients, not just stage 4 as in general guidelines. Urinary ACR screening should occur from age 18 (or younger if risk factors present) per RACGP guidelines.

Dietary Factors

Dietary phosphate restriction is challenging in remote communities where access to fresh produce is limited and processed foods (high in phosphate additives) are often the primary available option. Culturally appropriate dietary counselling from Aboriginal health workers or renal dietitians (via telehealth) improves adherence.

Medication Adherence

Phosphate binders must be taken with every meal — adherence is difficult with complex regimens. Lower pill-burden options (lanthanum chewable tablets) may improve adherence. PBS Authority Required applications for sevelamer and lanthanum can be completed by nephrologists or general practitioners with nephrology endorsement.

Vitamin D Deficiency

Despite living in a sun-rich country, vitamin D deficiency is common in Indigenous Australians, particularly in remote communities where sun exposure may be limited by cultural practices (e.g., covering skin for cultural reasons), chronic illness, and reduced outdoor activity. Cholecalciferol supplementation is essential and should be initiated empirically when testing is unavailable.

Cultural Safety

Management plans should be developed in partnership with Aboriginal health workers and community Elders. Yarning-based education about bone health, dialysis, and medication is more effective than written pamphlets. Sorry Business and cultural obligations may affect clinic attendance — flexible scheduling and outreach models improve engagement.

Referral Pathways

RHDAustralia and state/territory kidney services provide telehealth-enabled nephrology support for remote communities. The Northern Territory Remote Renal Services, Western Australia Country Health Service, and Queensland Health Indigenous renal programmes offer outreach dialysis and CKD-MBD management. Referral for specialist assessment should occur at CKD stage 4 (or earlier if rapidly progressing).

📚 References

1. Kidney Disease: Improving Global Outcomes (KDIGO) CKD-MBD Update Work Group. KDIGO 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease–Mineral and Bone Disorder (CKD-MBD). Kidney Int Suppl. 2017;7(1):1–59.
2. Kidney Disease: Improving Global Outcomes (KDIGO) CKD-MBD Work Group. KDIGO clinical practice guideline for the diagnosis, evaluation, prevention, and treatment of chronic kidney disease–mineral and bone disorder (CKD-MBD). Kidney Int Suppl. 2009;(113):S1–130.
3. Australia and New Zealand Dialysis and Transplant Registry. ANZDATA 46th Annual Report 2023 (Data to 2022). Adelaide: ANZDATA; 2023. Available from: https://www.anzdata.org.au
4. Elder GJ, Sherrard DJ. Calcium, phosphate, and vitamin D in chronic kidney disease. In: Turner N, editor. Textbook of Renal Disease. 2nd ed. Melbourne: Elsevier; 2020. p. 312–335.
5. Isakova T, Nickolas TL, Denburg M, et al. KDOQI US Commentary on the 2017 KDIGO Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease–Mineral and Bone Disorder (CKD-MBD). Am J Kidney Dis. 2017;70(6):737–751.
6. RACGP. Guidelines for Preventive Activities in General Practice. 9th ed. East