The Effect of Obesity on Response to Biological Drugs in Iraqi Patients with Seropositive Rheumatoid Arthritis

Background: The hallmark of rheumatoid arthritis, a prevalent systemic autoimmune disease, is a persistent, symmetrical, progressing inflammatory polyarthritis. The clinical results and disease activity of autoimmune rheumatic disorders, such as rheumatoid arthritis, are exacerbated by obesity. Adipose tissue is more widely acknowledged as a vital immunological organ and an endocrine gland which secretes a number of bioactive compounds known as "adipokines" than as a passive location for energy storage.

Objective: to assess how obesity affects individuals with seropositive rheumatoid arthritis’ reaction to various biological medications.

Patients and Methods: This retrospective analysis comprised 120 patients with seropositive RA who were receiving biological therapy for the previous 6 or 12 months; 90 of them were using anti-TNF medications (60 on Etanercept, 30 on Infliximab), and 30 on Rituximab. All patients' demographic information, length of illness, usage of steroids and disease-modifying anti-rheumatic drugs, their body mass index (BMI), and type and duration of biological treatment were documented. Additionally, the Erythrocyte Sedimentation Rate (ESR) and disease activity scores (Clinical Disease Activity Index (CDAI) as well as Disease Activity Score 28 (DAS28)) were assessed as a baseline before to the start of biological therapy (from registry data) and six or twelve months later.

Results: It was determined that there were no statistically significant differences between the Anti-TNF and Rituximab groups in terms of age, gender, BMI, or length of illness (P>0.05). According to the analysis, there was no significant inverse correlation between BMI and the decrease in CDAI, DAS28, and ESR in the Rituximab group (P>0.05), whereas there was in the Anti-TNF group (P<0.001), meaning that patients with higher BMIs responded less than those with normal BMIs. Gender also seems to be related to treatment response in the Anti-TNF group; using male gender as a reference category, female gender was significantly correlated with a greater decrease in CDAI and DAS28 (P<0.05), but not with the ESR (P>0.05). In contrast, there was no such gender correlation with treatment response in the Rituximab group.

Conclusions: In individuals with seropositive rheumatoid arthritis, obesity has been linked to a decreased clinical response to anti-TNF medications (Etanercept and Infliximab); however, obesity had no comparable impact on the patient's response to Rituximab. Furthermore, there was no comparable gender correlation for the clinical effects of Rituximab, and women had a stronger clinical response to anti-TNF medications than men did.