Background Although medication of rheumatoid arthritis (RA) has been improved by early intensive treatment using MTX and biological agents (BIO) for decades, treatment of concomitant disease in RA patients, such as osteoporosis (OP), will be more important to improve activity of daily living of RA patients. Although denosumab (DMB), an anti-RANKL antibody, was approved for treatment of OP in Japan in 2013, clinical data in real world is lacking in patients with RA.
Objectives To investigate the 12 months efficacy of DMB on OP in patients with RA (RA-OP) and predictors of efficacy from multicenter registry study in Japan (TBCR-BONE).
Methods 64 female cases with RA-OP were included in this study. Bone mineral density (BMD) of lumbar spine (LS-BMD) and total hip (TH-BMD) and bone turnover markers (P1NP and TRACP-5b) were measured at baseline and every 6 months to 12 months.
Results Mean age was 69 years old. Mean RA duration was 16 years. Mean DAS28-CRP was 2.7. 44% of cases had the past history of fracture. Mean FRAX was 26%. Daily teriparatide was used in 12 cases before DMB treatment. LS-BMD at 6m and 12m was significantly increased compared with baseline (4.3% and 5.9%) (Fig1). TH-BMD at 6m and 12m was significantly increased compared with baseline (3.1% and 4.0%) (Fig1). Mean decrease in P1NP were 39.9% at 6m and 34.3% at 12m. Mean decrease in TRACP-5b were 31.5% at 6m and 27.2% at 12m. Next, all cases were divided into two group, good outcome group (GO group) and non-good outcome group (non-GO group), by mean %increase of LS-BMD and PF-BMD at 12 months. %increase of LS-BMD at 6m in LS-GO group (n=31) was significantly larger than that in LS-non-GO group (n=30) (7.6% vs. 0.9%). Baseline P1NP in LS-GO group was also larger than that in LS-non-GO group (62.5μg/l vs. 45.4μg/l). There were no significant differences in changes of BTMs between two groups. %increase of TH-BMD at 6m in TH-GO group (n=30) was significantly larger than that in TH-non-GO group (n=31) (5.0% vs. 1.2%). There were no significant differences in changes of BTMs between two groups.
Conclusions DMB was effective in RA-OP. Early response of BMD and baseline P1NP level were suggested to be the predictors of the efficacy of DMB in RA-OP. Higher baseline P1NP and higher LS-BMD increase at 6m were the predictors of better LS-BMD increase at 12m. Higher TH-BMD increase at 6m was the predictors of better LS-BMD increase at 12m.
Disclosure of Interest None declared