Remission in rheumatoid arthritis by different criteria does not converge over the inflammatory markers

Abstract

Objective: Remission is an ideal target in the management of rheumatoid arthritis (RA). We compared American College of Rheumatology (ACR) 1981 preliminary definition of remission, European League Against Rheumatism (EULAR) disease activity score of 28 joints - C-reactive protein (DAS28 (3)-CRP) and DAS28 (3)-ESR (erythrocyte sedimentation rate) and newer ACR/EULAR remission criteria from 2011. We assessed the agreement between these definitions using kappa statistics in a real-time clinical scenario.

Materials and methods: This is a cross sectional study in which 460 patients' charts were reviewed. Their data on tender and swollen joint counts, visual analogue scale of patient global assessment (Pt GA), ESR and CRP were retrieved. One hundred patients who fulfilled one of the remission criteria and had all the required five variables were selected and they were categorized into remission using all the four definitions.

Results: Only one case out of 100 fulfilled all four remission criteria. Among 100 cases: ACR 1981 classified six in remission; ACR/EULAR 2011, eight; DAS28 (3)-ESR, 24; and DAS28 (3)-CRP classified 100 patients in remission. A substantial number of patients continued to have features suggesting persisting active inflammation, despite being categorized into remission. A major portion of disagreement was in ESR and CRP. The value spread of all clinical parameters such as swollen joint count, tender joint count and Pt GA had no significant difference in the patients classified as being in remission.

Conclusion: The DAS28 (3)-CRP overestimated remission compared to all other criteria. Disagreement was more in laboratory inflammatory parameters. A uniform definition of remission is needed.

Keywords: CRP; DAS score; ESR; remission; rheumatoid arthritis.