A FRAX Experience in Korea: Fracture Risk Probabilities with a Country-specific Versus a Surrogate Model

BACKGROUND Recently, a Korean fracture-risk assessment tool (FRAX) model has become available, but large prospective cohort studies, which are needed to validate the model, are still lacking, and there has been little effort to evaluate its usefulness. This study evaluated the clinical usefulness of the FRAX model, a FRAX developed by the World Health Organization, in Korea. METHODS In 405 postmenopausal women and 139 men with a proximal femoral fracture, 10-year predicted fracture probabilities calculated by the Korean FRAX model (a country-specific model) were compared with the probabilities calculated with a FRAX model for Japan, which has a similar ethnic background (surrogate model). RESULTS The 10-year probabilities of major osteoporotic and hip fractures calculated by the Korean model were significantly lower than those calculated by the Japanese model in women and men. The fracture probabilities calculated by each model increased significantly with age in both sexes. In patients aged 70 or older, however, there was a significant difference between the two models. In addition, the Korean model led to lower probabilities for major osteoporotic fracture and hip fracture in women when BMD was excluded from the model than when it was included. CONCLUSIONS The 10-year fracture probabilities calculated with FRAX models might differ between country-specific and surrogate models, and caution is needed when applying a surrogate model to a new population. A large prospective study is warranted to validate the country-specific Korean model in the general population.