Use of Oral Bisphosphonates in Primary Prevention of Fractures in Postmenopausal Women: A Population-Based Cohort Study

Oral bisphosphonates are first-line drugs in the treatment of osteoporosis under most guidelines, and have been shown to decrease risk of first fracture only in asymptomatic vertebral fractures and in clinical trial populations that are generally very different from the general population. OBJECTIVE: To compare incidence of first osteoporotic fracture in two cohorts of postmenopausal women, one treated with bisphosphonates and the other only with calcium and vitamin D. DESIGN: Retrospective population cohort study with paired matching based on data from electronic health records. SETTING: Women aged 60 years and older in 2005, from 21 primary care centers in a healthcare region of Spain. PARTICIPANTS: Two groups of women aged 60 years and older (n = 1208), prescribed either calcium and vitamin D (CalVitD) or bisphosphonates (BIPHOS) with or without calcium and vitamin D, were compared for the end point of first recorded osteoporotic-related fracture, with 5-years follow-up. MAIN OUTCOME MEASURE: Incidence of first fracture: Vertebral fracture, osteoporosis with pathological fracture, fracture of the upper humeral epiphysis, fracture of the lower radial epiphysis, or femur fracture. RESULTS: Estimated 10-year risk of fracture was 11.4% (95% confidence interval: 9.6 to 13.2), 11.8% (9.2 to 14.3) in the BIPHOS group and 11.1% (8.6 to 13.6) in the CalVitD group. No significant differences were found between groups in total fractures (Hazard ratio = 0.934 (0.67 to 1.31)) or location (vertebral, femoral, radial or humeral). CONCLUSIONS: In postmenopausal women, bisphosphonates have not been shown to better decrease risk of first fracture compared with calcium and vitamin D therapy alone.