Premenopausal women diagnosed with long-standing rheumatoid arthritis (RA) were observed to have systemic bone fragility at peripheral sites, according to study results published in Arthritis & Rheumatology. In addition, the study researchers indicated the association between bone erosions and cortical bone fragility and also between osteophytes and repair of trabecular bone.
The aim of the current study was to evaluate the bone microarchitecture and strength at the distal radius and tibia of premenopausal women with long-standing RA, as well as the association between systemic and localized bone involvement.
Researchers assessed volumetric bone mineral density (BMD) and performed microarchitecture and finite element analysis at the distal radius and tibia using high-resolution peripheral quantitative computed tomography (HR-pQCT). Erosions and osteophytes were also identified at the metacarpophalangeal and proximal interphalangeal joints using HR-pQCT.
A total of 80 premenopausal women with long-standing RA (mean age, 39.4±6.7 years; 60% White; disease duration, 9.8±5.3 years) were included in the study; 160 healthy control participants were matched by age and body mass index.
Compared with the control participants, patients with RA had impaired trabecular cortical volumetric BMD, as well as impaired microstructure and biomechanical parameters at the distal radius and tibia (P <.05).
Bone erosions occurred in 60 patients (75%) and osteophytes in 33 patients (41.3%). Compared with patients without erosions, those with erosions had lower cortical volumetric BMD at the distal radius (980±72 vs 1021±47 mg HA/cm3; P =.03), higher cortical porosity (2.8±2.5% vs 1.8±1.6%; P =.04), and higher trabecular thickness (0.067±0.011 vs 0.060±0.011 mm; P =.03). At the distal tibia, patients with erosions had lower cortical volumetric BMD (979±47 vs 1003±34 mg HA/cm3; P =.04) and higher cortical porosity (3.7±1.7% vs 2.7±1.5%; P =.01).
Trabecular volumetric BMD was positively correlated with osteophyte volume (0.392; P =.02), trabecular number (0.381; P =.03), cortical thickness (0.302; P =.09), bone stiffness (0411; P =.02), and failure load (0.419; P =.01); however, trabecular volumetric BMD was negatively correlated with trabecular separation (-0.364; P =.04).
Multiple regression analysis indicated that none of the HR-pQCT parameters had a statistically significant effect on presence of osteophytes, except disease duration and number of swollen joints (P =.04 for both).
Study limitations included the cross-sectional design and the sample size due to the exclusion criteria to avoid the potential influence of confounding factors for bone loss.
According to the researchers, “These data support that bone involvement in RA is not restricted to the subchondral bone but to a systemic involvement of bone tissue, with changes in bone microarchitecture, reduction in bone mass and bone fragility.”
Perez MO, Figueiredo CP, Sales LP, et al. Bone erosions and osteophytes in premenopausal women with long-standing rheumatoid arthritis: association with systemic bone involvement by HR-pQCT. Arthritis Rheumatol. Published online August 30, 2021. doi:10.1002/art.41961