We tried to characterize the serologic variables and MRI detection of early changes in the wrists and finger joints, allowing the differentiation of RA from rheumatic diseases other than RA (non-RA) at the earliest stage.113 consecutive, newly referred patients with polyarthritis, suspected of having early-stage RA, were enrolled in this study, and the diagnosis of having either RA or non-RA was established during the follow-up period. Logistic regression analysis was used to determine the variables at the entry that discriminated early-stage RA from non-RA, and statistical weight was calculated for each variable. 113 subjects included 80 early-stage RA (mean disease duration of 80 patients were 4.8 months) and 33 non-RA. Logistic regression analysis identified the presence of anti-cyclic citrullinated peptide antibody (anti-CCP antibody) and/or IgM rheumatoid factor (IgM-RF), symmetrical synovitis and bone marrow oedema and/or bone erosion on MRI as significant characteristic variables for early-stage RA. The sensitivity and specificity in total score of 2 or more of the three objective parameters (anti-CCP antibody and/or IgM-RF: 1, symmetrical synovitis on MRI: 1, bone marrow oedema and/or bone erosion on MRI: 1) in the classcification of RA were 82.5% and 84.8%. Our present data may indicate that the prediction of autoantibodies as well as MRI detection of early joint changes contribute to the accurate diagnosis of early-stage RA. In addition, the numbers of MRI-evidence of synovitis, bone erosion, mean E-rate, serum CRP, MMP-3 and IL-6 levels and percentage of patients with HLA-DRB1 *0405 allele carriership in early-stage RA patients were significantly higher in bone marrow oedema-positive than-negative group, suggesting bone marrow oedema reflects severe disease status in patients with early-stage RA, and could be clinically useful for monitoring disease outcome.
