Fracture risk assessment tool may not indicate bone fragility in women with type 2 diabetes

Abstract Background Diabetes carries a known risk of bone fracture despite high bone mineral density (BMD). The fracture risk assessment tool (FRAX) predicts the 10-year major osteoporotic fracture risk and hip fracture risk. We investigated the effects of clinical parameters on the FRAX score and evaluated the validity of FRAX for evaluating current bone fragility in diabetes subjects. Methods Forty-seven thousand, three hundred eighty-nine Japanese women participated in the Chiba bone survey, a population-based, multicenter, cross-sectional study of postmenopausal osteoporosis; we estimated FRAX scores without BMD and compared scores between subjects with and without type 2 diabetes. Results Mean FRAX major osteoporotic fracture risk was significantly higher in the diabetes group. A multiple regression model demonstrated some clinical parameters that affected the FRAX score and, after adjusting for such parameters, the FRAX score was not significantly different between the diabetes and non-diabetes groups, although the type 2 diabetes rate was significantly higher in subjects with a fracture in the past five years, which reflected current bone fragility. After adjusting for clinical parameters, the diabetes rate remained significantly higher in subjects with a fracture in the past five years, confirming that type 2 diabetes influences current bone fragility. Our study demonstrated that type 2 diabetes truly carries a risk of bone fracture, but adjusted FRAX major osteoporotic fracture risk isn't significantly different between subjects with and without type 2 diabetes. Conclusions The FRAX major osteoporotic fracture risk without BMD doesn't correctly indicate current bone fragility in Japanese middle-aged women with type 2 diabetes.