Osteoporosis and its consequent increase in fracture risk is a major health problem for postmenopausal women.(1) The disease is currently managed with a range of therapies that decrease bone resorption(2–4) or increase bone formation.(5) The response to treatment may depend on the patient's characteristics such as initial BMD(6) and osteoporotic status(7) or be independent of such factors.(8) Strontium ranelate is an orally active agent, which has been shown to both increase bone formation and reduce bone resorption in vitro and in animal models(9,10) and to improve bone architecture and bone resistance in rats.(11) In two large multinational studies of postmenopausal women with osteoporosis, a 3-year treatment with strontium ranelate 2 g/day orally was shown to reduce significantly the risk of vertebral and nonvertebral fractures by 41% over 3 years in the Spinal Osteoporosis Therapeutic Intervention (SOTI) study(12) and 16% in the Treatment of Peripheral Osteoporosis (TROPOS) study,(13) with a 36% reduction of risk of hip fracture in a high-risk population of the TROPOS study (a posteriori analysis performed in a subgroup of osteoporotic women with age ≥ 74 years).(13) The bone formation measured by bone alkaline phosphatase was increased compared with placebo, whereas the intensity of bone resorption measured by serum C-telopeptide crosslinks (sCTX) was decreased,(12) suggesting that strontium ranelate may dissociate bone formation and bone resorption. Among the different types of osteoporotic fractures, the clinical significance of vertebral fractures is now recognized because of the link between these fractures and increased mortality,(14,15) pain, disability, and impairment of quality of life.(16,17)
The aim of these analyses was to assess the efficacy of strontium ranelate according to the determinants of vertebral fracture and thus to determine which patients would benefit from this treatment.