Endocrine Abstracts

JOINT267

Introduction: Bone Health Index (BHI) is calculated from hand-wrist X-rays using BoneXpert® software: it assesses the average cortical thickness of the three middle metacarpal bones, adjusted for bone width and length. The software also provides a standard deviation score (BHI SDS) that allows comparison with healthy children with the same bone age. BHI has shown a significant correlation with fracture risk in a healthy pediatric population¹; however, its correlation with fractures in OI has not been evaluated. We hypothesise that BHI would correlate with fracture risk in Osteogenesis Imperfecta (OI) and thus be helpful in the assessment of bone fragility.

Methods: The National OI service at Great Ormond Street Hospital (London, UK) currently looks after 276 children with OI and maintains a detailed and accurate record of fractures. We retrospectively reviewed their first hand-wrist X-rays, fracture history in the one-year window before and after hand-wrist X-ray was performed, lateral spine X-rays, and DXA scans. All selected patients underwent hand-wrist X-rays and DXA scans on the same day, with X-rays analyzed using BoneXpert® version 3. 0 or later. The 132 cases previously analyzed with earlier software versions are currently being reanalyzed using the latest version and are not included in this preliminary analysis.

Results: A statistically significant negative correlation was observed between BHI SDS and the total number of vertebral and non-vertebral fractures within the year before and after BHI assessment (r = -0. 702, P = 0. 0001). This correlation was particularly strong for vertebral fractures (r = -0. 759, P = 0. 00002). A statistically significant positive correlation was observed between BHI and DXA BMD absolute values (r = 0. 610, P = 0. 0461), but no correlation between BHI SDS and DXA SDS values was observed. Interestingly, no significant correlation was found between lumbar DXA measurements (BMD, BMD SDS and BMAD SDS) and fracture incidence, even when analyzing vertebral and non-vertebral fractures separately. Post-pubertal patients showed higher BHI values than pre-pubertal patients. Additionally, patients with an Asian geographical background had lower BHI scores and sustained more fractures compared to patients with a Caucasian and African background

Conclusion: This preliminary analysis suggests that, unlike DXA, BHI correlates more closely with fracture risk, particularly for vertebral fractures. BHI may offer a feasible, cost-effective tool for identifying OI children at higher fracture risk.

Reference: 1. Prijatelj V et al. Bone health index in the assessment of bone health: The Generation R Study. Bone 2024