CKD, CKD-MBD and renal osteodystrophy

Q: What's the difference between Chronic kidney disease (CKD), chronic kidney disease-mineral and bone disorder (CKD-MBD), and "renal osteodystrophy"?

Answer:

Kidney Disease: Improving Global Outcomes (KDIGO) work group in 2006 recommended expanding the term chronic kidney disease (CKD) to chronic kidney disease-mineral and bone disorder (CKD-MBD) -when all three components are present, i.e.,

• Abnormalities of calcium, phosphorus, parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), and vitamin D metabolism
• Abnormalities in bone turnover, mineralization, volume linear growth, or strength
• Extraskeletal calcification

This is because as CKD advances, it involves mineral and bone metabolism disorders, manifested by either one or a combination of the above three components.

"Renal osteodystrophy" should be used exclusively to define alterations in bone morphology associated with CKD based upon bone biopsy, and it is only one component of the bone abnormalities of CKD-MBD. Further, depending on bone biopsy, it can be sub-classified as high-turnover, low-turnover, or mixed-bone disease. It is important to note that skeletal disorders that may occur in patients with CKD, like osteoporosis and bone cysts due to dialysis-related amyloidosis, are not included in the term renal osteodystrophy.

#nephrology

#metabolism

#wlectrolytes

#bone-disorders

References:

1. Moe S, Drüeke T, Cunningham J, et al. Definition, evaluation, and classification of renal osteodystrophy: a position statement from Kidney Disease: Improving Global Outcomes (KDIGO). Kidney Int 2006; 69:1945.

2. 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.

3. Pazianas M, Miller PD. Osteoporosis and Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD): Back to Basics. Am J Kidney Dis 2021; 78:582.