Ultrasound- and clinical-defined disease activities are associated with altered bone microarchitecture and lower bone mineral density in patients with rheumatoid arthritis.

Background/aims: We investigate if rheumatoid arthritis (RA) activity, defined clinically and with ultrasound, is associated with bone macro- and micro-architecture impairment on high-resolution peripheral quantitative computed tomography (HR-pQCT) and dual X-ray densitometry (DEXA).

Methods: Disease activity was evaluated in 61 RA patients, with clinical indices and ultrasound (hands and wrists). Bone mineral density (BMD) and architecture were analyzed with HR-pQCT and DEXA.

Results: Ultrasound RA disease activity parameters [synovitis, power doppler (PD)-positive joints, sum of positive power doppler signals and tenosynovitis] were associated with altered HR-pQCT bone density and structure at tibia or radius (trabecular volumetric BMD, trabecular bone volume fraction, trabecular thickness and cortical porosity). In addition, wrist ultrasound activity was specifically locally associated with impaired local bone microarchitecture at distal ipsilateral radius. Clinical and functional RA disease activity parameters (number of swollen joints, Health Assessment Questionnaire and disease activity score DAS28-CRP) were also correlated with HR-pQCT parameters (total and trabecular volumetric BMD, trabecular thickness and cortical thickness). At the hip, BMD correlated with VAS-fatigue and DAS28-ESR. The number of synovitis detected by ultrasound was higher when total hip T-score was lower than - 1.

Discussion: Ultrasound and clinical disease activity parameters were associated with impaired HR-pQCT parameters (distal radius and tibia), with lower trabecular and cortical bone densities and impaired bone microarchitecture (organization of spans and cortical porosity). In addition to systemic contribution to bone impairment, a local correlation between wrist US activity and HR-pQCT at distal radius was observed.

Conclusion: Patients with active RA, especially with US evaluation, are at higher risk for altered bone density and structure.