Absolute Fracture-Risk Prediction by a Combination of Calcaneal Quantitative Ultrasound and Bone Mineral Density

Quantitative ultrasound measurement (QUS) and bone mineral density (BMD) have each been shown to predict fracture risk in women. The present study examined whether a combination of QUS and BMD could improve the predictive accuracy of fracture risk. This is a population-based prospective study which involved 454 women and 445 men aged 62-89 years. Femoral neck BMD (FNBMD) was measured by DXA and calcaneal QUS was measured as broadband ultrasound attenuation (BUA) by a CUBA sonometer. Fragility fracture was ascertained by X-ray reports during the follow-up period, which took place between mid-1989 and 2009. During the follow-up period (median 13 years, range 11-15), 75 men and 154 women sustained a fragility fracture. In women, the model with FNBMD and BUA had a higher AUC compared to that without BUA (0.73 vs. 0.71 for any fracture, 0.81 vs. 0.77 for hip fracture, and 0.72 vs. 0.70 for vertebral fracture). Reclassification analysis yielded a total net reclassification improvement of 7.3%, 11.1%, and 5.2% for any, hip, and vertebral fractures, respectively. For men, the addition of BUA to FNBMD did not improve the predictive power for any, hip, or vertebral fracture. These results suggest that calcaneal QUS is an independent predictor of fracture risk and that a combination of QUS and BMD measurement could improve the predictive accuracy of fracture risk in elderly women.