Impact of obesity on clinical outcomes and treatment continuation in rheumatoid arthritis patients receiving non-TNF-targeted therapies

Abstract

Background: Recent studies have shown the impact of obesity on achieving low disease activity or remission in rheumatoid arthritis (RA) patients treated with tumor necrosis factor inhibitors. However, there is limited research on the effects of obesity on clinical responses to non-TNF-targeted treatments. Objectives: This study investigated the influence of body mass index (BMI) on clinical response to non-TNF-targeted treatments in RA patients. Design: We used data from the KOrean nationwide BIOlogics & targeted therapy (KOBIO) registry, a multicenter, prospective, observational cohort that included RA patients in South Korea. Methods: Patients who received at least one prescription for non-TNF-targeted treatments, including abatacept, tocilizumab, and Janus kinase inhibitors, were included. They were categorized into three BMI groups: under 25 kg/m 2 (434 patients), between 25 and 30 kg/m 2 (146 patients), and over 30 kg/m 2 (22 patients). After 1 year of treatment, treatment continuation rates and clinical responses among these BMI groups were compared. Time on treatment for each category was analyzed using Kaplan–Meier curves and Cox regression, adjusting for confounders. Results: The 1-year continuation rate of the targeted treatment was significantly lower in the obese group (81.8%) compared to the normal BMI (93.8%) and overweight (89.0%) groups ( p = 0.033). Disease Activity Score of 28 joints-erythrocyte sedimentation rate score improvement was less in the obese group (2.06 ± 2.14) than in the normal BMI group (2.76 ± 1.55) ( p = 0.045). Multivariable Cox proportional hazard analysis showed a higher discontinuation rate in the obese group (hazard ratio: 3.407, 95% confidence interval: 1.157–10.211; p = 0.029). Conclusion: Higher BMI in RA patients was associated with poorer clinical response and higher discontinuation rates for non-TNF-targeted treatments.