ULTRASOUND DISCRIMINATES PATIENTS WITH HIP FRACTURE EQUALLY WELL AS DUAL-ENERGY X-RAY ABSORPTIOMETRY AND INDEPENDENTLY OF BONE-MINERAL DENSITY

We measured the heels of 43 women who had recently sustained a hip fra cture and 86 age matched controls, using an Achilles(R) ultrasound dev ice. Average BUA, SOS, and Stiffness were significantly lower in fract ured patients (p < 0.0001). We also estimated ultrasound parameters fo r patients as a function of controls and found the mean BUA to be -1.0 9 SD compared with controls, the mean SOS -0.89 SD, and the mean Stiff ness -0.98 SD. Femoral BMD measured at the neck, Ward's triangle, and the trochanter with a DPX Plus(R) was also significantly lower in frac tured patients (p < 0.0001). The increased risk of hip fracture associ ated with low ultrasound values was estimated with logistic regression analysis for each bone parameter, adjusted for height and weight. The adjusted regression coefficients associated with BUA, SOS, Stiffness, and BMD were all significant (p < 0.0001) demonstrating the influence of all ultrasound and DXA parameters on the risk of hip fracture. Aft er adjusting the logistic regressions for BMD neck, BUA, SOS, and Stif fness were still significant independent predictors of hip fracture. S ensitivity and specificity of all measures were analyzed with the area under the ROC curve which were for BUA, 0.77 +/- 0.04; for SOS, 0.75 +/- 0.04; for Stiffness, 0.78 +/- 0.04; and for BMD, 0.74 +/- 0.04. We determined the range for the best compromise between sensitivity and specificity of BUA, 97-98 dB/MHz; SOS, 1482-1487 m/s; Stiffness 59-62% Young Adult; and of BMD, 0.64-0.69 g/cm(2). The area under the ROC cu rves of BUA, SOS, Stiffness, and DXA were compared and no statisticall y significant difference was found. Patients with trochanteric fractur es had significantly lower ultrasound parameters than those with cervi cal fractures (SOS and Stiffness p = 0.001, BUA p = 0.009), whereas no significant difference was found for DXA parameters (BMD neck, BMD Wa rd, and BMD trochanter p greater than or equal to 0.5). Some previous studies showed a lower bone density in patients with trochanteric frac tures and suggested that the two types of fractures might correspond t o a different process. Our results suggest that ultrasound is better c orrelated to the type of fracture than DXA, discriminates subjects wit h hip fracture equally well as DXA, and does indeed provide an indicat ion of fracture risk independent of BMD.