Background:  Bone health assessment is becoming an emerging issue in HIV-infected children and adolescents. Dual-energy x-ray absorptiometry (DEXA) has become the most commonly employed method for the assessment of bone health worldwide. However, its wide implementation in growing individuals is hampered by cost, radiation exposure, and size dependency of the measurements. Quantitative ultrasonography (QUS) has a special appeal for studying bone in children because of its speed, low cost, lack of ionizing radiation, and use of portable devices. To assess the applicability of QUS measurements in HIV-infected children, we related QUS bone measurements with those obtained by DEXA.

Methods:  We studied 88 HIV-infected youths, aged 4.8 to 22.1 years (43 boys and 45 girls). The majority (70%) of the patients had undetectable HIV viral load; 76 patients were receiving a protease inhibitor or NNRTI-based HAART, 6 patients were receiving a double NRTI regimen, and 6 patients were naïve to ART. Speed of sound was measured at the mid-shaft of the tibia and at the distal radius of non-dominant limb using a Sunlight Omnisense 7000 device. Bone mineral content (BMC) and density (BMD) of the lumbar spine, the whole skeleton, and the mid-shaft of the tibia were measured by DEXA (DPX-L, GE-Lunar).

Results:  The mean (SE) of speed of sound measurements at the radius was 3896 (15) m/s, while the mean speed of sound of the tibia was 3797 (16) m/s. Speed of sound of the radius correlated to lumbar spine BMC (r = 0.48) and BMD (r = 0.54), whole body BMC (r = 0.37) and BMD (r = 0.45) and SOS of the tibia correlated to lumbar spine BMC (r = 0.63) and BMD (r = 0.65), whole body BMC (r = 0.58) and BMD (r = 0.62). BMC and BMD of the mid-shaft of the tibia correlated with corresponding speed of sound measurements (r = 0.44 and r = 0.50, respectively).

Conclusions:  The correlations between DEXA and QUS indicate that the latter may be an additional diagnostic tools available to the pediatrician in the study of HIV-infected youths. Although the use of ultrasounds to predict fracture risk is still debated, there is evidence that speed of sound measurements are lower in children with fractures than non-fractured controls. Therefore, QUS could be a valid alternative in resources- and non-resources-limited settings where more complex devices for bone health assessment in pediatric HIV are not available.