The Relationship between Radial Bone Properties and Disease Activity and Physical Function in Individuals with Rheumatoid Arthritis

Abstract

People with rheumatoid arthritis (RA) are at increased risk for osteoporosis. This study explored the relationships between compartment-specific (cortical and trabecular) bone properties in the distal radius, a common site for osteoporotic fracture, and RA-related pain, upper-limb disease activity, and hand function in adults diagnosed within the previous 8 years. Cortical and trabecular bone properties (mass, density, and apparent trabecular structure) were assessed at the 4% site of the radius in 21 adults with RA using peripheral quantitative computed tomography (pQCT). Clinical measures included upper-limb active joint count; self-reported pain (AIMS-2 Arthritis Pain scale) and physical function (AIMS-2 Hand and Finger Function scale); and grip strength (modified sphygmomanometer). Associations were characterized using correlations (Pearson correlation coefficients or Spearman's rho). Cortical and trabecular bone mass and trabecular bone density were negatively associated with the number of active joints (r=-0.47, -0.54, and -0.47, respectively). Cortical bone density and mass were associated with grip strength (r=0.61 and 0.51, respectively). Cortical and trabecular bone density and cortical bone mass were negatively associated with scores on the Hand and Finger Function scale (r=-0.49, -0.45 and -0.56, respectively). Although the patterns differed slightly for cortical and trabecular bone, better bone health in both compartments was associated with fewer active joints and lower self-reported hand disability in adults with RA.