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 -2.5; 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 > or =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.