Fracture Risk Stratification by REMS: A 5 Years Prospective Longitudinal Multicentre Study

Osteoporosis is a skeletal disorder characterized by low bone mass and deterioration of bone microarchitecture. Current predictive tools, mainly based on DXA-BMD, do not full capture all the factors contributing to bone deterioration. By combining information on bone quantity (T-score) and skeletal fragility (Fragility Score, FS), the Radiofrequency Echographic Multi-Spectrometry provides an integrated measure of fracture susceptibility known as fracture risk stratification. We aimed To evaluate the ability of REMS fracture risk stratification through a 5 years prospective longitudinal multicentre study. A non-parametric Mann-Whitney test was used to assess differences of REMS T-score and FS between fractured and non-fractured patients. Additionally, Chi-squared tests, Cochran-Armitage trend tests, class-specific unadjusted logistic regressions and standardized residual analyses were performed to evaluate the proposed stratification model. A total of 4443 female patients was recruited and n = 4017 underwent REMS scans. The Chi-squared and the Cochran-Armitage trend tests showed that the distribution of fractured patients differed across the 7 risk classes with a strong positive monotonic trend at lumbar spine (Z = 47.83; p < 0.0001) and femoral neck (Z = 75.41; p < 0.0001). From a clinical perspective, both Class-specific binary logistic regression and standardized residuals clearly identified two opposite risk profiles: patients belonging to the low-risk classes exhibited a significantly reduced probability of fracture, whereas those in the high-risk classes showed a markedly increased fracture risk. This 5-year longitudinal study supports the clinical consistency of a REMS composite approach for fracture risk stratification based on the integration of REMS BMD T-score and Fragility Score.