Objective: To investigate the short-term effects of the tumour necrosis factor alpha (TNFalpha) antagonist infliximab on the acute phase reaction and activities of daily life (ADL) in patients with rheumatoid arthritis (RA).
Methods: Fourteen patients with active RA were treated with an intravenous infusion of 200 mg infliximab. The values of the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), fibrinogen, granulocyte count, lymphocyte count, platelet count and a patient questionnaire score on ADL, the Health Assessment Questionnaire (HAQ), were obtained at baseline and on days 4 and 14. The significance levels and effect sizes (ESs) of the changes from baseline were calculated.
Results: Changes by day 4: The ESs and significance levels were: CRP 1.7, p<0.005; lymphocyte count 1.4, p<0.005; fibrinogen 0.9, p<0.005; ESR 0.7, p<0.005; and HAQ 0.6, p<0.01. Changes by day 14: CRP 1.6, p<0.005; ESR 1.5, p<0.005; fibrinogen 1.3, p<0.005; lymphocyte count 1.0, p<0.005; granulocyte count 0.7, p<0.05; and HAQ 0.6, p<0.05.
Conclusion: CRP, fibrinogen and ESR showed the largest ESs and were thus the most sensitive variables showing the early effect of infliximab in this study. The score on ADL (HAQ) showed less ES, but still significant short-term improvements.