PREVENTION OF NONVERTEBRAL FRACTURES BY ALENDRONATE - A METAANALYSIS

Objective.-To evaluate the effect of treatment with alendronate sodium , a potent aminobisphosphonate, on the incidence of nonvertebral fract ures in postmenopausal women with osteoporosis. Data Sources.-Publishe d data and data on fi le at Merck Research Laboratories.Study Selectio n.-All completed prospective, randomized, placebo-controlled alendrona te trials of at least 2 years' duration (5 studies). Data Extraction.- All subjects were women with osteoporosis between the ages of 42 and 8 5 years, postmenopausal at least 4 years, with lumbar spine bone miner al density (measured using dual-energy x-ray absorptiometry) at least 2.0 SD below the mean for young adult women. All women randomized to t reatment with placebo or alendronate at a dose higher than 1 mg per da y for at least 2 years were included. Data Synthesis.-In the placebo g roup (n=590), 60 women reported nonvertebral fractures during 1347 pat ient-years at risk (overall rate, 4.45 women with fractures per 100 pa tient-years at risk), In the alendronate group (n=1012), 73 women repo rted nonvertebral fractures during 2240 patient-years at risk (overall rate, 3.26 women with fractures per 100 patient-years at risk). The e stimated cumulative incidence of nonvertebral fractures after 3 years was 12.6% in the placebo group and 9.0% in alendronate group. The rela tive risk for nonvertebral fracture estimated using the Cox proportion al hazards model was 0.71 (95% confidence interval, 0.502-0.997) (P=.0 48). A reduction in risk was consistent across each of the studies and at each major site of osteoporotic fracture, including the hip and wr ist. Conclusion.-In postmenopausal women with osteoporosis, treatment with alendronate reduces the risk of nonvertebral fractures over at le ast 3 years.