A HISTORY OF RECENT CLINICAL FRACTURE IS A STRONGER RISK FACTOR THAN LOW BMD IN PREDICTING 5-YEAR INCIDENCE OF CLINICAL FRACTURES

Background: Many risk factors for fractures are documented, but their relative value in determining the absolute risk (AR) for fractures within a well-defined time frame is not well documented. We therefore focused on the contribution of a history of recent clinical fracture compared to low BMD on the 5-year absolute risk (AR) for incident clinical fractures in postmenopausal women.Methods: A prospective general practice-based population study over 5 years was performed in 759 postmenopausal women aged 50-80 years.At baseline, clinical risk factors for fractures, including history of clinical fractures, and bone mineral density (BMD) in the lumbar spine were evaluated. Out of a random sample of 1684 women, 759 survivors accepted to participate five years later. They completed a questionnaire recording incident clinical fractures during follow up. Fractures were verified in the patient files at the general practice centres. Risk factors that were significantly related to incident clinical fractures in a univariate analysis were entered in a multivariate Cox survival regression analysis. Interaction between significant risk factors was verified.Results: Ninety-five women (12.5%) developed an incident fracture during the 5-year follow-up (3542 patient years). In multivariate analysis, low BMD (T-score <-1.0) (HR: 2.3; 95% CI: 1.3-4.2) and 5-year fracture history (HR: 7.0; 95% CI: 4.6-10.8), were significant independent predictors of incident fractures. Significant interaction was found between the 5-year fracture history and BMD in predicting fractures.In patients with a history of fracture during the last 5 years (n=68), the 5-year AR for incident fracture was 50.8% (95% CI: 48.5-53.0), with no significant effect of low BMD.In patients without a previous fracture during the last 5 years (n=691), the only significant predictor for incident fractures was low BMD (HR: 2.3; 95% CI: 1.3-4.2). In this group, the 5-year AR of incident fracture was 9.5% (7.4-11.5) in patients with low BMD and 6.6% (5.2-8.1) when BMD was normal.Conclusion: The 5-year AR for incident clinical fractures was significantly higher in patients with a recent history of a clinical fracture than in patients without a recent fracture history, even if these last had low BMD. These results suggest that risk factors that are related to recent clinical fractures, but that are not captured by measuring BMD (such as bone microarchitecture and fall risk), are more important predictors of clinical fractures at short term than low BMD.Citation: Ann Rheum Dis, volume 65, supplement II, year 2006, page 417Session: Osteoporosis