Relationship Between Bone Mineral Density Changes and Fracture Risk Reduction in Patients Treated With Strontium Ranelate

Abstract

Numerous randomized, controlled trials have shown that drugs can improve bone mineral density (BMD) and lower the risk of fracture, but in the case of antiresorptive agents the predictive value of changes in BMD remains controversial. Strontium ranelate has reduced bone resorption and increased bone formation at the same time in preclinical models, and recently was reported to significantly lower the risk of vertebral and other fractures in women with postmenopausal osteoporosis. The present study monitored vertebral and other fractures and BMD at several sites (lumbar spine, femoral neck, total proximal femur) during 1-3 years of treatment with strontium ranelate. A 3-year increase in BMD at the femoral neck and total proximal femur, but not in the spine, was significantly associated with a reduced incidence of new vertebral fractures. For each percentage point increase in femoral neck or total proximal femur BMD noted after 3 years, the risk of a new vertebral fracture developing after 3 years decreased by 3%. The 3-year changes in femoral neck and total proximal femur BMD accounted for 76% and 74%, respectively, of the reduction in vertebral fractures. No significant association was found between 3-year changes in BMD and the risk of new nonvertebral fractures. Nevertheless, an increase in femoral neck BMD after 1 year was significantly associated with the reduction in new vertebral fractures observed after 3 years of treatment.