Agreement between dual-energy X-ray absorptiometry derived bone mineral density and trabecular bone score for diagnosis of osteoporosis and low bone mineral density in adults living with cystic fibrosis — ASN Events
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Agreement between dual-energy X-ray absorptiometry derived bone mineral density and trabecular bone score for diagnosis of osteoporosis and low bone mineral density in adults living with cystic fibrosis (#356)

Akash Konantambigi 1 2 , Natasha Rajkumar 1 , Karen Hay 3 , Angela Matson 1 , Daniel Smith 4 , Joseph Lee 5 , Shanal Kumar 1 2
  1. Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Brisbane, QLD, Australia
  2. University of Queensland, Brisbane, QLD, Australia
  3. QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
  4. Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, QLD, Australia
  5. Department of Nuclear Medicine, The Prince Charles Hospital, Brisbane, QLD , Australia

Aims: To evaluate agreement between trabecular bone score (TBS) and bone mineral density (BMD) classification for osteoporosis and osteopenia in adults with cystic fibrosis (CF), and to identify clinical factors associated with impaired bone health and imaging discordance.

Methods: We conducted a retrospective cross-sectional study of adults attending a tertiary Australian Adult Cystic Fibrosis Centre who underwent dual-energy X-ray absorptiometry (DXA) between September 2021 and December 2024. Clinical, biochemical and imaging data were extracted from a prospectively maintained database. TBS was retrospectively derived from lumbar spine DXA images using validated software. Agreement between TBS and BMD classifications was assessed, and associations with clinical variables, fracture history and longitudinal imaging outcomes were explored.

Results: A total of 245 adults were included (58.8% male; median age 33.4 years). Overall, 39.6% of participants were classified as having impaired bone health based on either BMD or TBS. Osteoporosis was identified in 15.1% using spine BMD, 12.7% using hip BMD and 5.3% using TBS. Agreement between TBS and BMD classification was observed in 75% of hip assessments and 72% of spine assessments. Older age, lower forced expiratory volume in one second (FEV₁) and higher alkaline phosphatase were associated with impaired bone health. Older age and lower FEV₁ was also associated with greater discordance between TBS and BMD classifications. No significant associations were identified between fracture history and imaging, biochemical or clinical variables.

Conclusion: TBS and BMD demonstrated moderate agreement in skeletal classification among adults with CF. BMD identified a greater burden of skeletal impairment and remains the primary screening and diagnostic tool for CF-related bone disease. TBS may have an adjunctive role in selected individuals, particularly those with more advanced lung disease, although prospective studies are required to determine its incremental value for fracture risk prediction.