Strontium ranelate reduces the risk of nonvertebral fractures in postmenopausal women with osteoporosis: Treatment of Peripheral Osteoporosis (TROPOS) study

Background: Strontium ranelate, a new oral drug shown to reduce vertebral fracture risk in postmenopausal women with osteoporosis, was studied in the Treatment of Peripheral Osteoporosis (TROPOS) study to assess its efficacy and safety in preventing nonvertebral fractures also. Methods: Strontium ranelate (2 g/d) or placebo were randomly allocated to 5091 postmenopausal women with osteoporosis in a double-blind placebo-controlled 5-yr study with a main statistical analysis over 3 yr of treatment. Findings: In the entire sample, relative risk (RR) was reduced by 16% for all nonvertebral fractures (P = 0.04), and by 19% for major fragility fractures (hip, wrist, pelvis and sacrum, ribs and sternum, clavicle, humerus) (P = 0.031) in strontium ranelate-treated patients in comparison with the placebo group. Among women at high risk of hip fracture ( age >= 74 yr and femoral neck bone mineral density T score <=-3, corresponding to -2.4 according to NHANES reference) (n = 1977), the RR reduction for hip fracture was 36% (P = 0.046). RR of vertebral fractures was reduced by 39% (P < 0.001) in the 3640 patients with spinal x-rays and by 45% in the subgroup without prevalent vertebral fracture. Strontium ranelate increased bone mineral density throughout the study, reaching at 3 yr (P < 0.001): +8.2% (femoral neck) and +9.8% (total hip). Incidence of adverse events (AEs) was similar in both groups. Conclusion: This study shows that strontium ranelate significantly reduces the risk of all nonvertebral and in a high-risk subgroup, hip fractures over a 3-yr period, and is well tolerated. It confirms that strontium ranelate reduces vertebral fractures. Strontium ranelate offers a safe and effective means of reducing the risk of fracture associated with osteoporosis.