Long-term application of disease modifying antirheumatic drugs (DMARD). A single-center, observational study of 1681 patients with rheumatoid arthritis (RA).

Objective: To study the long-term efficacy and safety of methotrexate (MTX), intramuscular gold, azathioprine (AZA), chloroquine (CQ), sulphasalazine (SASP), and D-penicillamine (DPA) in rheumatoid arthritis (RA) patients.

Methods: Between 1979 and 1994, clinical data were prospectively gathered in a single center. 1681 patients were followed-up for at least 4 years. A 50% reduction of the swollen joint count was required to continue therapy. In addition, a modified Lansbury index, the Keitel function test, and laboratory parameters were determined every six months. Side effects leading to the discontinuation of treatment were recorded as well.

Results: After an observation period of more than four years, 39.6% and 28.3% of patients were taking MTX and AZA, respectively; 18.2% were receiving gold, 16.9% remained on DPA. SASP and CQ were still applied in 13.5% and 6.6%. MTX, AZA and SASP had a drop-out rate due to toxicity of 15.9%, 15.3% and 17.7%, whereas 34.8% had to discontinue CQ (gold: 27.4%, DPA: 26.9%). The majority of dropouts occurred within the first year of treatment. Subgroups of seropositive patients and patients with rheumatoid nodules had a poorer treatment efficacy irrespective of the DMARD.

Conclusion: In the long-term application, MTX was the most efficient compound, followed by AZA, whereas CQ had the poorest drug survival. Our results underline the value of long-term observations under the conditions of clinical practice as a supplement to controlled clinical trials.