Bone microarchitecture and fracture risk in rheumatoid arthritis

Abstract

   BACKGROUND: Microarchitecture of trabecular bone tissue can currently be evaluated using a special program for dual-energy X-ray absorptiometry (DXA) to determine the trabecular bone score (TBS).   AIM: to assess bone microarchitecture and fracture risk in patients with rheumatoid arthritis (RA).   MATERIALS AND METHODS: a cross — sectional study included 95 postmenopausal women with confirmed diagnosis of RA (mean age 62.3 ± 8.1 years). The survey was conducted using a specially designed questionnaire, laboratory examination, DXA of the lumbar spine (L1–L4) with the determined of TBS and proximal femur. The risk of major osteoporotic fractures (MOF) was assessed using FRAX calculator without or with TBS standardization.   RESULTS: 41 (43.2 %) patients had osteoporosis (OP) in at least one measurement area, while in L1–L4 — 26.3 %, in the femoral neck (FN) — 22.1 % and in total hip (TH) — 11.6 % persons. 35.8 % women had normal, 25.3 % — partially degraded and 38.9 % — degraded microarchitecture according to TBS. In patients with a history of fractures, low TBS was detected significantly more often than in people without fractures (p < 0.05). TBS was negatively correlated with age with age (r = -0.30, p = 0.003), duration of postmenopause (r = -0.26, p = 0.014), cumulative dose of glucocorticoids (GCs) (r = -0.34, p = 0.045) and positively correlated with BMD L1-L4 (r = 0.43, p < 0.001), BMD of the FN (r = 0.21, p = 0.038) and BMD TH (r = 0.23, p = 0.02). Normal BMD values in L1–L4 and at the same time degraded microarchitecture according to TBS were in 9.5 % RA persons. A high risk of fractures according to FRAX was detected in 47 (49.5 %) women, and FRAX adjusted for TBS increased the number of such patients to 52 (54.7 %).   CONCLUSION: OP was diagnosed in 43.2 % of postmenopausal women with confirmed RA, and 38.9 % had degraded bone microarchitecture by TBS. Negative associations were found between TBS and age, duration of postmenopause, cumulative dose of GCs, and positive associations with BMD in all parts of the skeleton. Including TBS values into the FRAX calculator made it possible to redistribute patients into risk groups, as a result of which 54.7 % of patients had a high risk of MOF.