SAT0145 Influence of body mass index (BMI) on the disease inflammatory activity and treatment reponse in patients with rheumatoid arthritis
Authors: A Villalba Yllan, V Navarro Compan, C Plasencia Rodriguez, D Peiteado Lopez, G Bonilla Hernan, L Nuño Nuño, A Martinez Feito, D Pascual-Salcedo, C Diego, A Balsa Criado
Journal: Annals of the Rheumatic Diseases (2017)

<h3>Background</h3> The use of biological therapy (BT) in rheumatoid arthritis (RA) has supposes a very important change in the disease9s treatment and prognosis. Drugs like Anti-TNFα have proven unquestionable effectiveness. However, the lack or loss of such effectiveness over time raises the dilemma of what factors may influence it. There are studies that suggest the influence of BMI on the efficacy of these drugs and therefore on the control of the disease. <h3>Objectives</h3> To determine the influence of BMI on disease activity and response to treatment with infliximab (ifx) in patients with RA. <h3>Methods</h3> A retrospective observational study of a population of 76 patients with RA who received infliximab treatment, in a standard guideline of 3 mg/kg, in our service between 2000 and 2016 inclusive. The BMI was classified for some sub-studies in four categories: low (&lt;18.5), normal (=18.5- &lt;25), overweight (=25- &lt;30) and obesity (=30). Disease activity was determined by DAS28 at three times: at baseline, at 6 months and at the year of infliximab treatment; Response to treatment was assessed by deltaDAS28 and EULAR response at 6 months and 1 year of treatment. The EULAR response was classified into two categories: "yes" (DeltaDAS28&gt;1.2, or&gt;0.6 and DAS28 &lt;5.1) and "no" (DeltaDAS28 &lt;.6, or &lt;5.1). First, activity and response rates to treatment were compared in these four groups over the three periods. A regression analysis was then performed for BMI and both activity and response to treatment. <h3>Results</h3> Characteristics of the 76 patients included in the study when initiating IFX therapy were: 66 (86.8%) were women, median (range) age 54 (21–83) years, 77,% RF+, 81% ACPA+, disease duration 10,8 (1,0–39,0) years, 59% with concomitant methotrexate and 55% with other DMARDs. Median (range) BMI was 25,5 (16,7–40,2) kg/m<sup>2</sup>. According to BMI, patients with underweight, normal, overweight and obesity were 0 (0,0%), 41 (53,9%), 22 (28,9%) and 13 (17,2%), respectively. The association between BMI and disease activity (median DAS28 (p25-p75)) is shown in Table 1: The association between BMI and treatment response (median deltaDAS28 (p25-p75) and EULAR response (%)) is shown in Table 2: In the longitudinal analysis, a trending but not statistically significant relationship between adjusted BMI and DAS28 was observed at six month and at one year of treatment onset: β: 0,051; 95% CI (-0,06 to 0,109) and β: 0,037; 95% CI (-0,022 to 0,097) <h3>Conclusions</h3> BMI seems to influence, in a non significantly manner, in disease activity and in treatment response in RA treated with infliximab. Obesity BMI values are associated with increased activity and a lower response to this treatment than lower BMI values. <h3>Disclosure of Interest</h3> None declared