Body mass index and response to abatacept in rheumatoid arthritis

Background Previous studies suggested that obesity could negatively affect the response to antitumour necrosis factor-alpha (TNF alpha) agents in rheumatoid arthritis (RA). However, data are lacking on whether obesity affects the response to abatacept (ABA). We aimed to determine whether body mass index (BMI) affects the response to ABA in RA. Materials and methods In this multicenter retrospective study, we included RA patients who received ABA. BMI was calculated at the initiation of treatment. After 6 months of treatment, change from baseline in DAS28, pain on a visual analog scale, erythrocyte sedimentation rate and C-reactive protein level, tender and swollen joint count were analysed. The primary endpoint was decrease in DAS28 >= 1.2. Secondary outcomes were good response and remission by EULAR criteria. Results At baseline, among 141 RA patients included, the median [interquartile range] BMI was 26.0 [22.930.8] kg/m(2). The number of patients with normal weight, overweight and obesity was 64 (45.4%), 38 (27%) and 39 (27.6%), respectively. Baseline characteristics did not differ among the three BMI subgroups. Univariate analysis revealed no difference in BMI between responders and nonresponders: DAS28 decrease >= 1.2 (25.0 [23.4-31.3] vs. 26.3 [22.9-30.2], P = 0.95), EULAR good response (26.4 [23.5-30.9] vs. 26.0 [22.9-30.6], P = 0.96) and remission (26.7 [21.7-30.3] vs. 26.0 [23.0-30.1], P = 0.83). Conclusion In our real-life study, BMI did not affect the response to ABA in RA. If confirmed, these results suggest that obesity is not a limitation of ABA use in RA.