OBJECTIVE: We retrospectively investigated the inhibitory effect on radiographic 
joint damage (RJD) for non-biological disease-modifying antirheumatic drug 
(non-bioDMARD) monotherapy or methotrexate (MTX) combination therapy for 
rheumatoid arthritis (RA) in the disease activity score with 28 joint counts 
with erythrocyte sedimentation rate (DAS28) remission.
METHODS: Eighty-four patients (55 cases of monotherapy, 29 cases of 
MTX-combination therapy) in DAS28 remission (DAS28 ≤ 2.6) were investigated from 
538 RA patients newly registered between February 2007 and August 2010. The 
patients were analyzed for radiological assessments using the modified total 
Sharp score/year (mTSS/y).
RESULTS: The remission rates and ΔmTSS/y for each agent using monotherapy were 
7.1% and 0.17 for sulfasalazine; 11.9% and 0.49 for bucillamine (BUC); and 23.9% 
and 2.06 for MTX. Those using combination therapy were 6.8% and 1.39 for MTX + 
BUC; 23.5% and -1.64 for MTX + leflunomide; and 8.0% and 0.31 for MTX + 
tacrolimus. The cumulative distribution in the single and combination therapy 
groups showed improvement of percentages in structural remission from baseline 
to 1-year treatment, 34.1% to 60.9% (P < 0.05) and from 0% to 56.7%(P < 0.0001), 
respectively. Baseline mTSS (r = 0.67, P < 0.0001), disease duration (r = 0.40, 
P < 0.01), swollen joint counts (r = 0.33, P < 0.05), and anti-cyclic 
citrullinated peptide antibody (r = 0.31, P < 0.05) were useful predictors of 
RJD for non-bioDMARD monotherapy, but not for combination therapy.
CONCLUSION: Satisfactory inhibition of RJD was observed in the DAS28 remission 
cases of monotherapy or MTX combination therapy with a non-bioDMARD.