Background Patients with rheumatoid arthritis (RA) show problems with bone metabolism. Bone mineral density (BMD) is lower in patients with RA than in healthy individuals 1. Whether biologic agents improve BMD and levels of bone mineral markers (BMM) in patients with RA remains controversial. No previous comparative studies have investigated the effects of each biologic agent on BMD and BMM.
Objectives We researched the influence of biologic agents on BMD and BMM in patients with RA using a prospective, comparative design.
Methods We performed this prospective, comparative study (the AIRTIGHT study; UMIN000005570) to investigate the effects of abatacept (ABT) and other biologic disease-modifying anti-rheumatic drugs (bDMARDs) on bone metabolism. A total of 165 RA patients were divided into an ABT group (n=50) and a Non-ABT group (n=115). The Non-ABT group received infliximab (n=15), etanercept (n=22), adalimumab (n=38), tocilizumab (n=26), or golimumab (n=14). We evaluated the percent change in BMD (%ΔBMD) of lumbar and femoral neck by using dual-energy X-ray absorptiometry. Urinary levels of cross-linked N-telopeptide of type I collagen (NTx) and bone-specific alkaline phosphatase (BAP) were used as markers of bone resorption and formation, respectively.
Results In this study, 64% (32/50) of the ABT group and 72% (83/115) of Non-ABT group completed biologic therapy for 1 year, showing no significant difference (p=0.387). No significant differences in BMD of the lumbar and femoral neck were seen as background factors (Table 1). In %ΔBMD of the lumbar spine, no significant difference was observed (ABT: -0.40±4.31%, Non-ABT: -1.67±5.07%; p=0.524). However, the increase in femoral neck BMD was significantly higher in the ABT group (0.97±8.63%) than in the Non-ABT group (-2.19±5.49%; p=0.047). No significant differences were observed in % change of NTx (ABT: -7.01, Non-ABT: -4.43; p=0.73) or BAP (ABT: 0.44, Non-ABT: 2.21; p=0.33). The efficacy for BMM was similar for each drug. A negative correlation was seen between both BMM and changes to BMD at the femoral neck (NTx: r=-0.248, p=0.0153; BAP: r=-0.303, p=0.0023).
Conclusions The increase in femoral neck BMD was significantly better in the ABT group than in the Non-ABT group. ABT may offer good efficacy for bone metabolism in patients with RA.
Haugeberg G, Uhlig T, Falch JA, et al. Bone mineral density and frequency of osteoporosis in female patients with rheumatoid arthritis: results from 394 patients in the Oslo County Rheumatoid Arthritis register. Arthritis Rheum 2000;43:522-30.
Disclosure of Interest None declared