Wednesday, 6 April 2005

Poster Abstracts: Osteoporosis - Prevention

Risedronate Reduces Fragility Fractures in Osteopenic Postmenopausal Women

Ethel S. Siris, MD, James A. Simon, M.D., Ian Barton, BSc, Michael R. McClung, MD, and Andreas Grauer, MD, PhD.

There is increasing evidence that a significant number of vertebral and non-vertebral osteoporotic fractures occur in patients with BMD values in the osteopenic range. Using data obtained from the VERT and BMD studies, we investigated the efficacy of risedronate in reducing osteoporotic fractures in postmenopausal women who had a baseline femoral neck BMD T-score above –2.5 SD and no prevalent vertebral fracture (VFx). Of the patients who met these inclusion criteria, 425 were from the BMD trials, and 282 were from the VERT studies. Initial BMD measurements were adjusted using NHANES-III data. This adjustment resulted in some women having T-scores greater than -1. Subjects from VERT had entered the trials based on a vertebral fracture diagnosed by investigators at individual study sites; however, this diagnosis was not confirmed in a number of patients when the radiographs were read by the central radiologist. We studied the effect of 3 years of risedronate 5mg vs. placebo daily on reducing the combined risk of vertebral and non-vertebral fractures. Patients were stratified per trial and data were analysed using a time-to-first fracture analysis. All patients received 1000mg calcium and, if needed, 500IU vitamin D/day. There were a total of 707 patients with a femoral neck T-score higher than -2.5 SD without prevalent VFx at baseline (355 on placebo, 352 on risedronate). They were well matched for mean age (64 vs. 64 years) and mean femoral neck T-score (-1.68 vs. -1.71). The fracture incidence in the placebo group over three years was 8.3%, compared to 2.1% in the risedronate-treated patients (RR 0.25, CI 0.09-0.67, p<0.006). Comparable results were found if the analysis was limited to osteopenic patients, defined by T-scores of -1 to -2.5 and no prevalent vertebral fractures (n=622). In this population, the incidence of fractures in the placebo group over three years was 6.4% compared to 2.1% in the risedronate-treated group (RR 0.25, CI 0.08-0.75, p=0.013). In conclusion, risedronate significantly reduced the risk for vertebral and non-vertebral osteoporotic fractures over 3 years in patients with a femoral neck T-score higher than -2.5 and no prevalent VFx by 75%. In addition to its established fracture risk reduction in osteoporotic patients, these data demonstrate that risedronate also significantly reduces the risk of both spine and non-spine fractures in patients without prevalent VFX and femoral neck-BMD values in the osteopenic range.

Disclosure Information:

Faculty Member's Name: Ethel S. Siris, MD
Grants/Research Support: N/A
Consultant: Procter and Gamble
Stock Shareholder (directly purchased): N/A
Other Financial or Material Support: None
I have no relationships to disclose.


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