Assessment of non-vertebral fracture risk in postmenopausal women

Background: Non- vertebral ( NV) fractures are responsible for a great amount of morbidity, mortality and cost attributable to osteoporosis. Objectives: To identify risk factors for NV fractures in postmenopausal women with osteoporosis, and to design an assessment tool for prediction of these fractures. Methods: 2546 postmenopausal women with osteoporosis included in the placebo groups of three risedronate controlled trials were included ( mean age 72 years, mean femoral T- score 22.5; 60% and 53% of patients with prevalent vertebral and NV fractures, respectively). Over 3 years, 222 NV fractures were observed. Baseline data on 14 risk factors were included in a logistic regression analysis. Results: 6 risk factors were associated with NV fracture risk: prevalent NV fracture ( p = 0.004), number of prevalent vertebral fractures ( p, 0.001), femoral T- score ( p = 0.031), serum level of 25- hydroxyvitamin D ( p, 0.001), age ( p = 0.012) and height ( p = 0.037). An NV risk index was developed by converting the multivariate logistic equation into an additive score. In the group of women with a score >= 2.1, the incidence of NV fracture was 13.2% ( 95% CI 11.1 to 15.3), 1.5 times higher than that of the general population. Conclusions: The NV risk index is a convenient tool for selection of patients with osteoporosis with a high risk for NV fractures, and may help to choose from available treatments those with a proven efficacy for reduction of NV fracture risk.