Predictors of near-term fracture in osteoporotic women aged ≥65 years, based on data from the study of osteoporotic fractures

D. Weycker, J. Edelsberg, R. Barron, M. Atwood, G. Oster, D. B. Crittenden, A. Grauer

Using data from the Study of Osteoporotic Fractures (SOF), several clinical characteristics predictive of near-term (1-year) risk of hip and non-vertebral fracture among elderly osteoporotic women were identified, and a subset of those for hip fracture was incorporated into a risk assessment tool. Additional research is needed to validate study findings. While several risk factors are known to contribute to long-term fracture risk in women with osteoporosis, factors predicting fracture risk over a shorter time horizon, such as over a 1-year period, are less well-established. We utilized a repeated-observations design and data from the Study of Osteoporotic Fractures to identify factors contributing to near-term risk of hip fracture and any non-vertebral fracture, respectively, among osteoporotic women aged ≥65 years. Potential predictors of hip fracture and any non-vertebral fracture over the 1-year period subsequent to each qualifying SOF exam were examined using multivariable frailty models. Because the discriminative ability of the hip fracture model was acceptable, a corresponding risk-prediction tool was also developed. Study population included 2499 women with osteoporosis, who contributed 6811 observations. Incidence of fracture in the 1-year period subsequent to each exam was 2.2% for hip fracture and 6.6% for any non-vertebral fracture. Independent predictors of hip fracture included low total hip T-score, prior fracture, and risk factors for falls (multivariable model c-statistic = 0.71 (95% CI 0.67-0.76)). Independent predictors of any non-vertebral fracture included age, total hip T-score, prior falls, prior fracture, walking speed, Parkinson's disease or stroke, and smoking (multivariable model c-statistic = 0.62 (0.59-0.65)). Several clinical characteristics predictive of hip and non-vertebral fracture within a 1-year follow-up period among elderly women with osteoporosis were identified, and a subset of those for hip fracture was incorporated into a risk assessment tool. Assessment of these risk factors may help guide osteoporosis treatment choices by identifying patients in whom there is urgency to treat. Additional research is needed to validate the findings of this study and the accuracy of the risk assessment tool.