Oral alendronate increases bone mineral density and reduces vertebral fracture incidence in postmenopausal osteoporosis

An international multicentre clinical trial studied the effects of oral alendronate (ALN) on bone mineral density (BMD), the incidence of fracture and loss of height in 994 women with postmenopausal osteoporosis, defined as a lumbar spine BMD at least 2.5 S.D. below the young adult mean. Twenty per cent of women had at least one vertebral fracture at baseline. The patients were randomized to receive placebo or ALN 5 or 10 mg daily for 3 yr or 20 mg daily for 2 yr followed by 5 mg for 1 yr. All women received 500 mg supplemental calcium daily with the evening meal. Patients had baseline BMD measured by dual energy X-ray absorptiometry, measurement of height and assessment of vertebral deformity. The women who received ALN had significant, progressive increases in BMD, whereas the women who received placebo showed a loss in BMD. For example, at 3 yr the women who received ALN 10 mg daily had increases of 8.8 +/- 0.4% in the spine, 5.9 +/- 0.5% in the femoral neck, 7.8 +/- 0.6% in the trochanter and 2.5 +/- 0.3% in the total body. Alendronate treatment was also associated with a 48% reduction in new vertebral fractures, less of a loss of height, and a decreased progression of vertebral deformities.