We tested the efficacy of infliximab treatment in 20 patients with rheumatoid arthritis (RA) using the following outcome measures; ACR (The American College of Rheumatology) core set, ACR-N, DAS (Disease Activity Score)28, and SDAI (Simplified Disease Activity Index). We also assessed the value of these indices and the adverse effects. The dosage of infliximab was adjusted for 3 mg/kg of body weight during the observation period (24 months). Of the 20 patients (average age 47 years old), 55% of patients achieved an ACR20 response at week 6.40% achieved ACR50 and 17% achieved ACR70 responses. In accordance with DAS28CRP, 60% of patients achieved good response. 20% achieved moderate response and 20% achieved no response. ACR-N and SDAI reflect disease activity in the same way as DAS28CRP, and these indices statistically showed a significant correlation. These results suggested that ACR-N, DAS and SDAI which numerically evaluate disease activity showed a good criterion-related validity. It was difficult to predict the prognosis using these indices at week 6 because there were some cases with amelioration after 6 weeks. It raised the possibility that CRP, ESR, rheumatoid factor, tender joint count and pain VAS might be prognostic factors, but there were individually no statistically significant differences. Frequent adverse effects of infliximab are pyrexia, headache, eruption, bacterial pneumonia, etc, and the trend was similar to previous reports. Further, we experienced a rare case of thrombocytopenia associated with the appearance of IgM anticardiolipin antibody, and we naturally need to take care of adverse effects such as infectious diseases.
