Bone Strength Significantly Lower in Patients With ACPA-Positive Rheumatoid Arthritis

Bone strength is significantly reduced among men and women with anti-citrullinated protein antibody (ACPA)-positive rheumatoid arthritis (RA) and is associated with the development of osteoporotic fractures, according to the results of a microfinite element analysis published in the Annals of the Rheumatic Diseases.

Investigators from the University of Erlangen-Nuremberg in Germany measured failure load and bone stiffness based on computed tomography data in patients with ACPA-positive RA, patients with ACPA-negative RA, and healthy control participants. Total, trabecular, and cortical bone densities, along with microstructural parameters of bone, were also analyzed.

A total of 276 participants were evaluated. Failure load and stiffness of bone were both significantly decreased in patients with ACPA-positive RA (P <.001), but not in those with ACPA-negative RA, compared with healthy control participants. Lower bone strength affected both men and women with ACPA-positive RA and was linked to longer disease duration and was significantly associated with the occurrence of osteoporotic fractures (stiffness of bone, P =.020; failure load, P =.012).

Impaired bone strength was linked to altered bone density and microstructural parameters, both of which were decreased in patients with ACPA-positive RA. According to multivariate models, ACPA status and sex were both independently associated with reduced biomechanical properties of bone in patients with RA (P =.007 and P <.001, respectively).

The investigators concluded that in patients with ACPA-positive RA, bone strength is significantly decreased, which is associated with the risk for fracture. The researchers note that reduced bone strength in patients with ACPA-positive RA is caused by profound changes in bone volumetric density and microarchitecture that resemble the structural features of bone seen in healthy individuals who are 20 years older.

follow @RheumAdvisor

Reference

Stemmler F, Simon D, Liphardt AM, et al. Biomechanical properties of bone are impaired in patients with ACPA-positive rheumatoid arthritis and associated with the occurrence of fractures [published online February 23, 2018]. Ann Rheum Dis. doi:10.1136/annrheumdis-2017-212404