Prevention of nonvertebral fractures by alendronate. A meta-analysis. Alendronate Osteoporosis Treatment Study Groups.

OBJECTIVE

To evaluate the effect of treatment with alendronate sodium, a potent aminobisphosphonate, on the incidence of nonvertebral fractures in postmenopausal women with osteoporosis.

DATA SOURCES

Published data and data on file at Merck Research Laboratories.

STUDY SELECTION

All completed prospective, randomized, placebo-controlled alendronate trials of at least 2 years' duration (5 studies).

DATA EXTRACTION

All subjects were women with osteoporosis between the ages of 42 and 85 years, postmenopausal at least 4 years, with lumbar spine bone mineral density (measured using dual-energy x-ray absorptiometry) at least 2.0 SD below the mean for young adult women. All women randomized to treatment with placebo or alendronate at a dose higher than 1 mg per day for at least 2 years were included.

DATA SYNTHESIS

In the placebo group (n=590), 60 women reported nonvertebral fractures during 1347 patient-years at risk (overall rate, 4.45 women with fractures per 100 patient-years at risk). In the alendronate group (n = 1012), 73 women reported nonvertebral fractures during 2240 patient-years-at risk (overall rate, 3.26 women with fractures per 100 patient-years at risk). The estimated cumulative incidence of nonvertebral fractures after 3 years was 12.6% in the placebo group and 9.0% in alendronate group. The relative risk for nonvertebral fracture estimated using the Cox proportional hazards model was 0.71 (95% confidence interval,0.502-0.997) (P=.048). A reduction in risk was consistent across each of the studies and at each major site of osteoporotic fracture, including the hip and wrist.

CONCLUSION

In postmenopausal women with osteoporosis, treatment with alendronate reduces the risk of nonvertebral fractures over at least 3 years.