Development of a nomogram for individualizing hip fracture risk in men and women

Abstract

Until now there has been no published prognostic tool available for predicting of hip fracture to primary care settings. We have developed a nomogram for predicting the absolute risk of hip fracture for any individual by using clinical factors, including age, prior fracture and fall, in addition to BMD that was based on a 15-year follow-up cohort study.

Introduction: Bone mineral density or clinical risk factors alone are useful but limited tools for the identification of individuals with high-risk of hip fracture. It is hypothesized that the combination of clinical risk factors and BMD can improve the accuracy of fracture prediction. This study was aimed at developing a nomogram which combines these factors for predicting 5-year and 10-year risk of hip fracture for an individual.

Methods: The study, designed as a epidemiologic, community-based prospective study, included 1,208 women and 740 men aged 60+ years with median duration of follow-up of 13 years (inter-quartile range, IQR: 6-14) for both women and men, yielding 10,523 and 7,586 person-years of observation, respectively. Main outcome measures were incidence of hip fractures and risk factors were femoral neck bone mineral density (FNBMD), prior fracture, history of fall, postural sway and quadriceps strength. Femoral neck BMD was measured by DXA (GE-LUNAR Corp, Madison, Wisconsin, USA). Cox's proportional hazards model was used to estimate the risk of fracture for individuals, and a nomogram was constructed for predicting hip fracture risk.

Results: Between 1989 and 2004, 127 individuals (96 women) sustained a hip fracture. Advancing age, low femoral neck BMD, prior fracture and history of falls were independent predictors of hip fracture. The area under the receiver operating characteristic curve for the model was 0.85 for both sexes. A nomogram was constructed for predicting hip fracture risk for an individual. Among those aged 75 or older with BMD T-scores < or = -2.5, the risk of hip fracture in men was comparable to or higher than in women; however, in younger age groups, the risk was higher in women than in men.

Conclusion: The combination of BMD and non-invasive clinical risk factors in a nomogram could be useful for identifying high-risk individuals for intervention to reduce the risk of hip fracture.