Background/Purpose:  After more than twenty years using Disease Modifying Drugs (DMARDs) is widely known their efficacy in the treatment of Rheumatoid Arthritis (RA) but it is necessary to increase our knowledge on how they work in the long-term in clinical practice. The purpose of this study is to assess the long-term survival of DMARDs (synthetic and biological) and the causes of discontinuation in patients with recent onset of Rheumatoid Arthritis (RA).

Methods:  Observational longitudinal study was conducted. Recent onset RA patients diagnosed between April 15^th 2007 and 31^st December 2010 followed in out-patient clinic at Hospital Clinico San Carlos until December 31^st 2015, which used any DMARD treatment were included. Primary outcome: DMARDs discontinuation due to: adverse drug reaction (ADR: moderate or severe), inefficacy, patient decision, improvement, and other causes. Incidence rates of discontinuation (IR) per 100 patient-years were estimated using survival techniques with their respective 95% confidence interval [CI].

Results:  We included 293 courses of DMARDs treatment in 97 patients (815 patient-years). Of these, 78% were women with a mean age at diagnosis of 55.6 ± 15 years. The median time to the start of the first DMARD was 0[0-41] days. 11.5% were taking biological DMARDs, 60.75% were using combined therapy and 86% were taking corticoids. We found 171 discontinuations with an IR of 21 [18-24.4] mainly due to ADR (IR: 13.5[11.2-16.2]) followed by inefficacy (IR: 2.6 [1.6-3.9]). The median survival was 2.6[1.9 to 4] years. The IR of discontinuation related to synthetic and biological DMARDs was 20.4 [17.4-23.9] and 27.2 [17.2-42.3] respectively. The crude IR of discontinuation was higher for Gold (IR: 36.5[22-59]) and Leflunomide (IR: 32.0[21.2-48.1]) being 11.1 [8.2-15] for Methotrexate. Regarding types of regimens, monotherapy had an IR of 17.94[13.9-23.1] whereas combined therapy had an IR of 23.1 [19.2-27.8].

Conclusion:  The discontinuation rate is estimated in 21 per 100 patients-year, being ADR the most common cause. Synthetic DMARDs seem to have more survival than biological, being Methotrexate the drug with lowest crude IR of discontinuation rate. Monotherapy seems to have more survival rate than combined therapy. This study contributes to increasing knowledge of the long-term survival of these drugs in real life.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/survival-of-disease-modifying-antirheumatic-drugs-in-rheumatoid-arthritis/