Body Mass Index and response to rituximab in rheumatoid arthritis.

Introduction: Previous studies suggested that obesity could negatively affect the response to anti-TNFα agents, but data are lacking on how it affects the response to rituximab (RTX). We aimed to determine whether body mass index (BMI) is involved in the response to RTX in RA.

Methods: We retrospectively analyzed data for 114 RA patients receiving RTX. Change from baseline in DAS28, pain on a visual analog scale, erythrocyte sedimentation rate, C-reactive protein level, tender and swollen joint count was analyzed at 6 months. The primary outcome was decrease in DAS28 ≥ 1.2. Secondary outcomes were EULAR good response and remission.

Results: At baseline, the median [interquartile range] BMI was 26.8 [23.8-31.1] kg/m(2). The number of patients with normal weight, overweight and obesity was 38, 41 and 35, respectively. After 6 months, the number of RA patients with DAS28 decrease ≥ 1.2 and EULAR good response and remission was 44 (38.6%), 27 (23.7%) and 24 (21.1%), respectively. In univariate analysis, the median BMI was similar among responders and non-responders for DAS28 decrease ≥1.2 (26.9 [24.1-30.1] vs. 26.8 [23.2-31.6], P=0.78), EULAR good response (27.7 [24.3-30.7] vs. 26.7 [22.3-31.5], P=0.57) and remission (26.9 [24.1-30.8] vs. 26.8 [23.2-31.5], P=0.94). Adjusted multivariable analysis confirmed a lack of association between BMI and different responses measures to RTX. BMI was only negatively associated with decreased ΔSJC (P=0.0276) and ΔTJC (P=0.0233).

Conclusion: BMI did not affect the response to RTX in RA. These data could help physicians to choose biologic agents for obese RA patients.