The value of changes in CRP and ESR for predicting treatment response in rheumatoid arthritis

Abstract

AbstractAim: During treatment of rheumatoid arthritis (RA) the serum C‐reactive protein (CRP) and erythrocyte sedimentation rate (ESR) decrease concurrent with clinical improvement. The aim of this paper is to investigate whether changes of these parameters could predict treatment response.Methods: Patients with active RA, requiring disease‐modyfying antirheumatic drugs were entered into the study. Serum CRP and ESR were assessed at baseline and 24 weeks after the treatment. Response to treatment was assessed by the RA Disease activity Score 28 (DAS28) and DAS28‐CRP response criteria. In statistical analysis the agreement between changes of CRP and ESR at the first stage of the treatment and DAS28/DAS28‐CRP were determined as ‘good’, ‘moderate’ and ‘none’ responses. The relationship between changes in CRP and DAS28‐CRP, ESR and DAS28 were also determined and compared.Results: Sixty‐six patients with active RA entered the study. The mean age was 50 ± 18 years and the mean disease duration was 4.9 ± 5.8 years. After an average period of 24 weeks, 51 patients met the DAS28 and 49 patients met the DAS28‐CRP response criteria as good or moderate responders. Over the treatment period a reduction of serum CRP predicted 90% of DAS28‐CRP responders and reduction of ESR predicted 97% of DAS28 responders, whereas a lack of CRP or ESR reductions predicted 54% and 45% non‐responders, respectively. Overall, the accuracy of changes in CRP and ESR in predicting treatment response according to DAS28‐CRP and DAS28 response criteria were 77% and 73%, respectively. CRP/DAS28‐CRP was more sensitive but less specific than ESR/DAS28 in predicting treatment response.Conclusion: Changes of CRP or ESR at the first stage of treatment can predict treatment response. Hence, measurement of serum CRP and ESR furnishes a reliable quantitative means for early anticipation of treatment response.