Risedronate treatment and extended fracture protection in postmenopausal women.

Sir, I would like to provide some perspective with regard to a published comment (1) on our study of risedronate treatment in postmenopausal women with vertebral fracture (2). The author suggests that risedronate is not effective in reducing vertebral fracture risk after the first year, and that the effects of risedronate "do not compare favorably" with those of alendronate and raloxifene. This assertion is not supported by the data, which show that both risedronate and alendronate produce 3-year vertebral fracture reductions in the range of 40% to 50% in women with baseline vertebral fractures (2-4); the effect of raloxifene 60 mg in a similar population was about 30% (5). The long-term effects of risedronate on sustaining fracture benefit are now available from a 5-year placebo-controlled study (6). This study demonstrates that the reduction in new vertebral fractures observed in the first 3 years of treatment with risedronate (5 mg daily) is sustained through 5 years. The observed 49% reduction in vertebral fracture risk during the 4th and 5th years of risedronate therapy is quite comparable to the fracture risk reduction observed during the first 3 years of treatment. Consistent results were also observed for risk reduction for non-vertebral fractures. In his comment, the author also fails to consider the demons t rated effi c a cy of ri s e d ro n ate in preventing nonve rt eb ra l fractures (2, 3, 7); a recent large study found that 3 years of risedronate treatment reduces the risk of hip fracture by 60% in osteoporotic women with baseline vertebral fracture (7). In summary, in contrast to the author's conclusions, treatment with risedronate 5 mg daily has demonstrated a rapid and sustained fracture efficacy that, together with a favorable safety profile, make it an appropriate first-line option for treatment of women with postmenopausal osteoporosis.