Decoding the Correlation Between Inflammatory Response Marker Interleukin-6 (IL-6) and C-reactive Protein (CRP) With Disease Activity in Rheumatoid Arthritis.

Abstract

Excessive interleukin-6 (IL-6) production in rheumatoid arthritis (RA) leads to joint destruction, inflammation, and systemic symptoms. IL-6 inhibitors alleviate symptoms. C-reactive protein (CRP), an inflammation biomarker, correlates with RA activity. In this study, we assessIL-6 and CRP levels in RA patients to understand their association with disease activity. This cross-sectional study was conducted at a tertiary care hospital in central Indiafor 15 months, from July 2022 to September 2023. The study involved 75 participants diagnosed with RA and receiving outpatient treatment. Exclusion criteria included anti-IL-6 drug treatment, bedridden individuals, proxy patients, and those without consent. Disease activity was assessed using the 28-joint disease activity score (DAS28), while IL-6 and CRP levels were measured following the standard procedures. The average CRP levels were found to be 51.67 ± 47.49 mg/L, while IL-6 levels averaged 65.16 ± 43.67 pg/ml. The results revealed a substantial positive correlation between IL-6 levels and DAS28 (r = 0.603, p value < 0.001), indicating a significant association. Additionally, a moderate correlation between CRP levels and DAS28 (r = 0.493, p value < 0.001) highlighted a significant relationship between these variables. The analysis showed that higher IL-6 levels were associated with increased disease activity and suggested IL-6 as a valuable indicator for assessing RA severity. Also, CRP levels had a moderate correlation with disease activity. Overall, IL-6 is a better marker for disease activity when compared to CRP levels in patients with RA.