Hand Bone Loss in Early Rheumatoid Arthritis Is Independent of Adalimumab Treatment – Results from a Randomized Controlled Clinical Trial.

BACKGROUND/PURPOSE: Rheumatoid arthritis (RA) is characterised by progressive destruction of joint bone and loss of periarticularbone mineral. Hand bone loss (HBL) measured by Digital X-ray Radiogrammetry (DXR) has been proposed as a sensitive outcome measure for treatment effect and as a potential predictor of subsequent radiographic progression in RA patients. We aimed to investigate the effect of adding adalimumab to a methotrexate and intra-articular triamcinolone treat-to-target strategy on one-year hand bone loss (HBLone-year) in early rheumatoid arthritis (RA) and to determine if HBL6months is associated with radiographic progression after two years. METHODS: In a clinical trial (OPERA) of 180 treatment-naive early RA patients (1), bone mineral density (BMD) was estimated from hand radiographs with Digital X-ray radiogrammetry (DXR) at baseline, after 6 months (n=90) and 12 months (n=70) of follow-up. Baseline and two-year radiographs were scored according to the Sharp/van der Heijde method. Baseline characteristics and HBL6months (0-6 months changes in DXR-BMD) were investigated as predictors of structural damage by univariate linear (DTotal Sharp/van der Heijde Score (TSS) as dependent variable) and logistic (+/-radiographic progression (DTSS>0) as dependent variable) regression analyses. Variables with p<0.10 were included in multivariable models. RESULTS: In 70 patients with available HBLone-year data, HBLone-year was median (InterQuartileRange(IQR)) -1.9 (-3.3;-0.26 mg/cm2) in the placebo-group and -1.8 (-3.6;0.06) mg/cm2 in the adalimumab-group, p=0.98,Mann Whitney (Figure 1). Increased HBL (compared to general population reference values (2)) was found in 26/37 and 23/33 patients in the placebo- and adalimumab-groups, Chi-sq=0.99. In 90 patients with HBL6months data and two-year radiographic data, HBL6months was independently associated with DTSS after two years (β=-0.086 (95% Confidence Interval=-0.15;-0.025) TSS unit/mg/cm2 increase,p=0.006), and borderline associated with presence of radiographic progression (DTSS>0) (OR 0.96(0.92-1.0), p=0.10). CONCLUSION: In early RA, adding adalimumab to a methotrexate-based treat-to-target strategy had no impact on HBLone-year, which was increased in both treatment groups. HBL6months was independently associated with DTSS after two years