The aim was to estimate the proportion of patients with rheumatoid arthritis (RA) achieving low disease activity by anti-tumor necrosis factor-alpha (TNF-α) therapy in an ordinary clinical setting.

Thirty-three patients with active RA despite methotrexate treatment were included in an open phase IV study of infliximab in combination with methotrexate. The mean age was 53years (range 21-71) and mean disease duration 10.7years (1-32). Treatment was changed in cases of insufficient response or intolerable adverse events. Response status to infliximab was assessed according to the American College of Rheumatology (ACR 20). Disease activity score (DAS28) was assessed at baseline and at weeks 26, 54, 80, 106 and 158. Low disease activity is defined as DAS28 ≤3.2.

ACR20 response to infliximab was recorded in 73% and 33% of the patients at weeks 26 and 158, respectively. Infliximab was discontinued in 16 patients, 15 of whom started other anti-TNF-α therapy. The baseline DAS28-score of 6.3 (95% CI 5.9-6.6) was significantly reduced after 26weeks to 4.1 (95% CI 3.6-4.7) and was later nearly stable. Low DAS28 was achieved by 36% of the patients at week 26, and by 15-24% at later assessments.

RA disease activity was significantly reduced, but DAS28 ≤3.2 was recorded in only 1/4 of the assessments. Increasing this proportion should be subject to continuous quality improvement efforts.