FRI0169 Influence of Body Mass Index (BMI) on Serum Levels of Infliximab in Patients with Rheumatoid Arthritis (RA)

BackgroundLoss of response of TNFα inhibitors (TNFi) over time resulting in discontinuing of this therapy is a major issue in RA, but underlying reasons for this remains unknown. A few studies suggest the influence of BMI on serum levels of subcutaneous TNFi. However, there is no available data on the possible influence of BMI on infliximab (IFX) serum levels, which is intravenously administred and adjusteing the dose according to patient weight.ObjectivesTo determine the possible influence of BMI on serum IFX levels in patients with RA.MethodsRetrospective observational study incluiding 72 patients with RA treated with infliximab, at 3 mg/kg dose in a standard regimen, in our department between 2000 and 2015. Serum IFX levels were determined by ELISA in 3 visits: i)2 weeks, ii)six months and iii)one year after treatment onset. BMI (kg/m2) was classified in four categories: underweight (