Abatacept might increase bone mineral density at femoral neck for patients with rheumatoid arthritis in clinical practice: AIRTIGHT study

We investigated the influence of abatacept (ABT) on bone mineral density (BMD) and bone metabolic markers (BMMs) in patients with rheumatoid arthritis (RA) compared to other biologic disease-modifying anti-rheumatic drugs (bDMARDs). This prospective, comparative, non-randomized study (the AIRTIGHT study; UMIN000005570) investigated the effects of ABT and other bDMARDs on bone metabolism. A total of 165 RA patients were divided into ABT (n = 50) and non-ABT (n = 115). We evaluated percentage changes in BMD (%Delta BMD) at the lumbar spine and femoral neck using dual-energy X-ray absorptiometry. Urinary levels of cross-linked N-telopeptide of type I collagen (uNTx) and bone-specific alkaline phosphatase (BAP) were used as markers of bone resorption and formation, respectively. No significant differences in 1-year completion rates were seen between ABT (64%) and non-ABT (72%; p = 0.387). The %Delta BMD at the femoral neck was significantly higher in the ABT group (0.97%) than in the non-ABT group (- 2.19%; p = 0.026). Whereas, no significant difference in %Delta BMD at the lumbar spine was observed between groups (ABT, - 0.40%; Non-ABT, - 1.67%; p = 0.524). No significant differences were observed in changes to uNTx or BAP. ABT treatment was significantly associated with increased BMD at the femoral neck (odds ratio (OR) 8.84; 95% CI 1.08-72.4; p = 0.04), and baseline lumbar osteoarthritis was significantly associated with BMD at the lumbar spine (OR 2.97; 95% CI 1.23-7.13; p = 0.02). The efficacy of ABT for increasing BMD at the femoral neck was superior to that of other bDMARDs. ABT may offer good efficacy for improving BMD at the femoral neck in patients with RA.