Aim: To investigate whether overweight/obesity at diagnosis affects the chances of decrease in disease activity and pain in early rheumatoid arthritis (RA).
Method: We investigated incident RA cases from the population-based Epidemiological Investigation of risk factors for Rheumatoid Arthritis (EIRA) study (2006-2009, N=495) with clinical follow-up in the Swedish Rheumatology Quality Register. At diagnosis, 93% received disease-modifying antirheumatic drugs (DMARDs) (86% methotrexate). The odds of achieving a good response according to the DAS28-based European League Against Rheumatism (EULAR) criteria, low disease activity (DAS28<3.2), remission (DAS28<2.6) or pain remission (visual analogue scale ≤20 mm) at 3-months and 6-months follow-up, were calculated using logistic regression, adjusting for potential confounders.
Results: Significant dose-response relationships were found between Body Mass Index (BMI) and change of disease activity as well as pain at both time points. Patients with BMI ≥25 had 51% lower odds of achieving low disease activity (odds ratio (OR=0.49 (95% CI 0.31 to 0.78)) and 42% lower odds of remission (OR=0.58 (95% CI 0.37 to 0.92)) at the 6-months visit, compared to normal-weight patients. This effect was also present at 3 months, where we also found a 43% decreased odds of pain remission (OR=0.57 (95% CI 0.37 to 0.88)). No effect modification was found for anti-citrullinated protein antibody (CCP)-status, sex, prednisolone treatment or DAS28 at diagnosis.
Conclusions: Overweight at diagnosis significantly decreases the chance of achieving good disease control during the early phase of RA.
Keywords: Disease Activity; Early Rheumatoid Arthritis; Epidemiology; Rheumatoid Arthritis.
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