Bone Health Index (BHI): a Fracture Risk Assessment tool in Children with Osteogenesis Imperfecta
Ruggero Lanzafame, Alistair D Calder, Belinda Crowe, Catherine DeVile, Moira S CheungAbstract
Introduction
Current tools to evaluate fracture risk in children with Osteogenesis Imperfecta (OI) are limited and bone mineral density (BMD) has limitations and is not widely available for children under 5 years. We hypothesized that the Bone Health Index (BHI), evaluating the average cortical thickness of the three middle metacarpal bones, adjusted for bone width and length, could be a useful tool in the assessment of fracture risk, particularly in infants.
Methods
The service at Great Ormond Street Hospital (London, UK) follows a cohort of over 277 children with classical OI and keeps a detailed and accurate record of confirmed fractures. We reviewed their BHI (analysed using the latest version of BoneXpert® software) at presentation (n = 123), the lumbar BMD (n = 47) taken on the same day where available, the subsequent two years fracture history and annual lateral spine X-rays.
Results
In multivariable logistic regression, each 1-SD decrease in BHI SDS was independently associated with a 5.3-fold higher odds of incident fracture within two years (OR 5.26, 95% CI 2.4–11.1, p < 0.001), while DXA BMD and BMAD Z-scores were not independent predictors. ROC analysis showed good discriminatory performance for BHI SDS (AUC 0.84), superior to DXA BMD Z-score (AUC 0.60) and BMAD Z-score (AUC 0.51).
Conclusions
Our study indicates that lower BHI SDS values are associated with increased fracture risk in children with classical OI. In the available DXA subgroup, BHI demonstrated stronger discriminatory performance than DXA-derived measures. BHI may represent a clinically useful complementary tool for fracture risk stratification in young children with OI, particularly where DXA is unavailable or technically limited, including infancy.