Treatment failure with disease-modifying antirheumatic drugs in rheumatoid arthritis patients.

INTRODUCTION: Rheumatoid arthritis (RA) patients taking disease-modifying antirheumatic drugs (DMARDs) may experience treatment failure due to adverse effects or a lack of efficacy/resistance. The purpose of this study was to evaluate the prescription patterns, the incidence and reasons for failure, and the time to treatment failure of DMARDs in RA patients. METHODS: The medical records of patients visiting the Rheumatology Clinic were scrutinised retrospectively in order to extract the relevant data, including demographics, clinical and laboratory investigations and drug usage, for analysis. RESULTS: More than 60% of the 474 eligible patients were started on a combination of DMARDs. Hydroxychloroquine (HCQ) (79.7%) and methotrexate (MTX) (55.6%) were the most common DMARDs prescribed initially. There was a significant difference in survival times among the various treatment groups (p ≤ 0.001). Adverse effect was the main reason for treatment failure of sulfasalazine (SSZ) (88.9%) and MTX (75%), while addition or substitution DMARDs was more common for those taking HCQ (72.2%). Adverse event was reported as the most significant predictor of treatment failure. The most commonly reported adverse effects were bone marrow suppression and hepatotoxicity. CONCLUSION: A combination of DMARDs was used to initiate therapy in more than 60% of RA patients, with HCQ and MTX being prescribed most frequently. Adverse effects accounted mainly for treatment failures with MTX and SSZ, while lack of efficacy was responsible for major treatment failures with HCQ.