Disease activity in rheumatoid arthritis: fibrinogen is superior to the erythrocyte sedimentation rate

Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are the most widely used assays to measure the laboratory aspect of the acute-phase response, being of great value in monitoring disease activity in rheumatoid arthritis (RA). The ESR is influenced by several factors, and mainly by fibrinogen. Therefore the relationships between ESR, fibrinogen and CRP and their correlations with a patient questionnaire score on activities of daily living, the Modified Stanford Health Assessment Questionnaire (MHAQ) were studied. Fifty-four consecutive patients with RA admitted to the hospital were recruited to this cross-sectional study. Strong mutual correlations were found between the studied acute-phase markers (p<0.000000001). Fibrinogen and CRP rates showed highly significant correlations with MHAQ, whereas ESR did not. We suggest that ESR could be replaced by fibrinogen in the assessment of RA in order more accurately to assess the slower component of the acute-phase response and to have a variable that shows better correlation with disability.