Bone status in rheumatoid arthritis assessed at peripheral sites by three different quantitative ultrasound devices

Rheumatoid arthritis (RA) is characterized by periarticular and generalized loss of bone mass. Quantitative ultrasound (QUS) has been introduced as a method for the assessment of bone status and fracture risk. In this cross-sectional study bone status was assessed by QUS at different peripheral sites in 27 women with RA (mean disease duration 15 years) and in 36 healthy women matched for age, height and weight. Speed of sound (SOS, m/s), broadband ultrasound attenuation (BUA, dB/MHz) and stiffness of the calcaneus were assessed by a Lunar Achilles device. Amplitude-dependent SOS (Ad-SOS, m/s) of the second to fifth phalanx was measured by a DBM Sonic 1200, and SOS of the distal forearm and third phalanx was measured by a Omnisense multisite scanner. Bone mass (g/cm² or g) of the hip, spine, distal forearm and total body was measured by dual-energy X-ray absorptiometry. QUS values were significantly reduced in RA at most sites (p < 0.005-0.001), but between-group differences were small, and large overlaps between the groups were noticed. After correction for bone mass, the observed differences remained statistically significant for the calcaneus and distal radius (p < 0.05). Independent associations between ultrasound measures and markers of disease activity were not demonstrated. In conclusion, bone status as assessed by QUS was compromised in RA, but whether ultrasound transmission may serve as a marker of disease progression and fracture risk in the individual patient remains to be clarified in prospective studies.