From the Guidelines
Adynamic Bone Disease (ABD) in Chronic Kidney Disease (CKD) patients is most accurately diagnosed through bone biopsy, which is considered the gold standard for diagnosis, as it reveals low bone turnover with reduced osteoblast and osteoclast activity, decreased bone formation rate, and minimal osteoid accumulation 1.
Diagnosis of Adynamic Bone Disease
The diagnosis of ABD in CKD patients involves a combination of biochemical markers, bone biopsy, and imaging techniques. However, due to the invasive nature of bone biopsies, clinicians often rely on biochemical markers, including:
- Low or low-normal parathyroid hormone (PTH) levels (typically below 150 pg/mL)
- Normal or low serum alkaline phosphatase
- Low levels of bone turnover markers such as osteocalcin and procollagen type 1 N-terminal propeptide (P1NP) Imaging studies like bone mineral density tests may show decreased bone mass, though these are not specific for ABD.
Clinical Features and Monitoring
Clinical features that raise suspicion of ABD include:
- Hypercalcemia
- History of excessive calcium or vitamin D supplementation
- Aluminum exposure
- Diabetes mellitus
- Older age
- Peritoneal dialysis treatment Regular monitoring of PTH and mineral metabolism parameters is essential in CKD patients to detect ABD early, as the condition increases fracture risk and contributes to vascular calcification 1.
Bone Biopsy
Bone biopsy is recommended if knowledge of the type of renal osteodystrophy will impact treatment decisions, as it provides a definitive diagnosis of ABD 1. The biopsy should be performed after tetracycline labeling and obtained from the anterior iliac crest using an instrument designed to obtain a core of bone of at least 4 to 5 mm diameter, with results reported in accordance with the standard nomenclature suggested by the American Society of Bone and Mineral Research 1.
Treatment Decisions
Therapeutic decisions should be based on trends in serum PTH levels instead of 1-time values, and bone biopsy should be considered if the results could lead to changes in therapy 1.
From the FDA Drug Label
Adynamic bone disease may develop if iPTH levels are suppressed below 100 pg/mL. One clinical study evaluated bone histomorphometry in patients treated with cinacalcet for 1 year. Three patients with mild hyperparathyroid bone disease at the beginning of the study developed adynamic bone disease during treatment with cinacalcet Two of these patients had iPTH levels below 100 pg/mL at multiple time points during the study.
The diagnosis of Adynamic Bone Disease (ABD) in patients with Chronic Kidney Disease (CKD) is based on bone histomorphometry and iPTH levels. If iPTH levels are suppressed below 100 pg/mL, there is a risk of developing ABD.
- Key factors to consider in the diagnosis of ABD include:
- iPTH levels: below 100 pg/mL
- Bone histomorphometry: to evaluate bone disease 2
From the Research
Diagnosis of Adynamic Bone Disease (ABD) in Patients with Chronic Kidney Disease (CKD)
The diagnosis of Adynamic Bone Disease (ABD) in patients with Chronic Kidney Disease (CKD) involves several methods, including:
- Histomorphometric analysis of tetracycline double-labeled bone biopsies, which is considered the gold standard for precise diagnosis 3
- Biochemical parameters, such as low intact parathyroid hormone (PTH) and low bone alkaline phosphatase levels, which may be suggestive of ABD 3, 4
- Dual X-ray absorptiometry, which is the standard diagnostic modality for identification of low bone mineral density, but may not be accurate in CKD patients 5
- Bone biopsy with non-decalcified histopathology, which remains the gold standard for the identification and evaluation of bone disorders, including osteoporosis and renal osteodystrophy 5
Characteristics of Adynamic Bone Disease (ABD)
ABD is characterized by:
- Low bone turnover 3, 6
- Low bone volume 3, 5
- Normal mineralization 3
- Markedly decreased cellularity with minimal or no fibrosis 3
- Low or zero bone formation rate and a reduction or absence of osteoblasts and osteoclasts 6, 7
Biochemical Markers for Adynamic Bone Disease (ABD)
Several biochemical markers have been proposed for the diagnosis of ABD, including:
- Low serum levels of alkaline phosphatase of bone origin, which is a good marker of ABD in haemodialysis patients 4
- Low intact PTH levels, which may be suggestive of ABD, but may not be accurate in all cases 3, 4
- Low osteocalcin levels, which may be associated with ABD, but are not as sensitive or specific as bone alkaline phosphatase or intact PTH 4