Comparison of fracture, cardiovascular event, and breast cancer rates at 3 years in postmenopausal women with osteoporosis

Objectives: To compare event rates for osteoporotic fractures, cardiovascular events, and breast cancer in postmenopausal women with osteoporosis. Design: A prospective, observational study of the placebo group in the double-blind, randomized Multiple Outcomes of Raloxifene Evaluation trial. Setting: One hundred eighty clinical research centers in 25 countries. Participants: Postmenopausal women (n=2,565, mean age=67) with osteoporosis were given calcium (500 mg/d) and vitamin D (400-600 IU/d) supplements. Measurements: The occurrence of at least one new fracture, cardiovascular event, or breast cancer diagnosis at 3 years was identified and adjudicated. Results: The occurrence of any fracture was the most common event in these women. In women without prevalent vertebral fractures (n=1,627), the event rates per 1,000 patient-years were 45.4 for any fracture, 15.2 for vertebral fracture, 4.7 for clinical vertebral fracture, 0.9 for hip fracture, 8.3 for any cardiovascular event, and 5.2 for all breast cancer. In women with prevalent vertebral fractures (n=938), the event rates per 1,000 patient-years were 117.4 for any new fracture, 77.1 for new vertebral fracture, 25.7 for clinical vertebral fracture, 5.8 for hip fracture, 15.1 for any cardiovascular event, and 2.6 for all breast cancer. The effect of prevalent fracture status on event rates was not dependent on whether women were older or younger than 65, but women aged 65 and older had a 3.6 times greater occurrence of cardiovascular events than younger women, irrespective of prevalent fracture status. Conclusion: These data on the relative incidence of clinically significant skeletal and extra-skeletal outcomes may be useful in choosing an agent for health maintenance for postmenopausal women with osteoporosis.