The Impact of Obesity on Inflammatory Markers Used in the Assessment of Disease Activity in Rheumatoid Arthritis

Background: Rheumatoid arthritis (RA) is a systemic inflammatory disorder in which raised C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are indicators of active disease. Obesity can falsely raise acute phase reactants in obese patients with RA, independent of disease activity. Objectives: to study the obesity effect on the levels of CRP and ESR among patients with rheumatoid arthritis in low disease activity or remission state. Patients and Methods: A cross-sectional study was conducted at the Rheumatology Unit of Baghdad Teaching Hospital in 2023. The study included 126 adult rheumatoid arthritis patients (70 obese and 56 non-obese), that had previously been diagnosed by a rheumatologist (according to the 2010 American College of Rheumatology criteria/ European League Against Rheumatism). The participants were aged 18 years and with CDAI < 10, and 50 obese healthy controls. Demographic and disease characteristics of patients were collected. Results: the mean age for RA patients and obese healthy controls was comparable. The F: M ratio of study participants was 3.2: 1. RA obese patients had significantly higher mean CRP levels than nonobese patients, while the differences of elevated ESR in both groups were insignificant, while the differences in ESR level between obese RA patients and obese healthy controls was significant, unlike CRP level differences between the two groups were insignificant. Conclusion: Obesity may falsely elevate CRP and ESR in RA patients with low disease activity or remission states by 25% and 10%respectively.Clinicians must be cautious while treating such patients.