Use of oral bisphosphonates in primary prevention of fractures in postmenopausal women: a population-based cohort study.

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.