Early effects of raloxifene on clinical vertebral fractures at 12 months in postmenopausal women with osteoporosis.

BACKGROUND: Raloxifene hydrochloride therapy reduces the risk for vertebral fractures at 3 years, but the effects on clinical vertebral fractures in the first year are not known.

METHODS: The Multiple Outcomes of Raloxifene Evaluation (MORE) Trial enrolled 7705 women with osteoporosis, defined by prevalent vertebral fractures and/or a bone mineral density (BMD) T score at or below -2.5, who were treated with placebo or raloxifene at a dosage of 60 or 120 mg/d for 3 years. New clinical vertebral fractures were defined as incident vertebral fractures associated with signs and symptoms suggestive of vertebral fractures, such as back pain, and were diagnosed by means of postbaseline adjudicated spinal radiographs. Scheduled spinal radiographs were obtained at baseline and at 2 and 3 years. In addition, unscheduled spinal radiographs were obtained in women who reported signs or symptoms suggestive of vertebral fracture, and these radiographs subsequently underwent adjudication. If an adjudicated fracture was identified, this was also considered a clinical fracture.

RESULTS: At 1 year, raloxifene, 60 mg/d, decreased the risk for new clinical vertebral fractures by 68% (95% confidence interval [CI], 20%-87%) compared with placebo in the overall study population, and by 66% (95% CI, 23%-89%) in women with prevalent vertebral fractures, who are at greater risk for subsequent fracture. The risk for clinical vertebral fractures in the raloxifene, 60 mg/d, group was decreased by 46% (95% CI, 14%-66%) at 2 years and by 41% (95% CI, 17%-59%) at 3 years. The cumulative incidence of new clinical vertebral fractures was lower in the group receiving raloxifene, 60 mg/d, compared with placebo (P<.001). We found no significant differences in the risk reductions for clinical vertebral fractures between the raloxifene groups at 1, 2, or 3 years.

CONCLUSION: The early risk reduction for new clinical vertebral fractures with 1 year of raloxifene treatment was similar to that reported with other antiresorptive agents.