POS0629 PREDICTORS OF CHANGE IN DISEASE ACTIVITY IN RHEUMATOID ARTHRITIS AFTER START OF TREATMENT WITH ABATACEPT
Authors: J. Liukkonen, G. Cagnotto, J. Å. Nilsson, S. Saevarsdottir, C. Turesson
Journal: Annals of the Rheumatic Diseases (2021)

Background: Abatacept is a biologic disease-modifying anti-rheumatic drug (bDMARD) used to treat rheumatoid arthritis (RA) since 2006, acting by inhibition of T-cell co-stimulation. There are limited data on factors predicting clinical outcomes in RA after start of treatment with abatacept. Objectives: The primary aim was to identify predictors of change in disease activity in RA-patients after start of treatment with abatacept. Methods: This cohort study was based on data from the Swedish Rheumatology Quality register (SRQ). All patients with RA who started treatment with abatacept between 2006 and 2017 were included. Clinical data from the SRQ included demographics, disease characteristics and antirheumatic treatment. Disease activity was measured according to DAS28-ESR (Disease Activity Score of 28 joints based on erythrocyte sedimentation rate) at inclusion and at follow-up visits at 6 and 12 months from start of treatment with abatacept. Baseline predictors of change in disease activity were investigated using linear regression models bivariately and adjusted for baseline values of DAS28. Covariates with a p-value of &lt;0.1 were retained for the final multivariate model. In case of covariates with major collinearity, the one with the stronger association with change of DAS28 was selected. Results: In a total of 2716 patients, 872 had data on change in DAS28 at 12 months. Among these, most patients were women (79.6%) and the mean age at start of abatacept was 58.4 years (SD 13.6). The majority of patients had established RA, with a mean disease duration of 13.5 years (SD 11.1). Most patients had severe, active disease, with substantial pain and disability, despite extensive treatment. The mean number of bDMARDs that a patient had been exposed to was 1.90 (SD 1.32). DAS28 decreased significantly over the first year (mean 1.22: 95 % CI 1.12, 1.32). The greatest decrease in DAS28 (mean 1.09) occurred during the first 6 months from start of abatacept. The multivariate regression model identified male sex and limited previous bDMARD exposure as independent predictors of change in DAS28 at 12 months from start of abatacept – adjusted for baseline DAS28, RA duration and current treatment with methotrexate or prednisolone (Table 1). Table 1. Determinants for retransitioning Bivariate Adjusted for baseline DAS28 Multivariate Variables B 95% CI P-value B 95% CI P-value B 95% CI P-value Male sex 0.39 [0.13, 0.64] 0.003 0.43 [0.20, 0.66] &lt;0.001 0.42 [0.19, 0.64] &lt;0.001 Age (per SD) 0.10 [-0.004, 0.21] 0.058 0.044 [-0.051, 0.14] 0.37 N/A RA duration (per SD) -0.14 [-0.25, -0.037] 0.008 -0.11 [-0.21, -0.016] 0.022 -0.030 [-0.13, 0.065] 0.54 HAQ (per SD) 0.12 [0.007, 0.23] 0.037 -0.24 [-0.35, -0.13] &lt;0.001 N/A VAS pain (per SD) 0.26 [0.15, 0.37] &lt;0.001 -0.058 [-0.17, 0.054] 0.31 MTX 1 0.20 [-0.013, 0.41] 0.066 0.17 [-0.018, 0.36] 0.076 0.11 [-0.076, 0.29] 0.25 Prednisolone 1 -0.19 [-0.41, 0.017] 0.072 -0.17 [-0.36, 0.024] 0.087 -0.14 [-0.33, 0.043] 0.13 bDMARDs 2 (per SD) -0.30 [-0.40, -0.20] &lt;0.001 -0.32 [-0.41, -0.23] &lt;0.001 -0.31 [-0.40, -0.21] &lt;0.001 B=beta coefficient; N/A=not applicable; SD=standard deviation; CI=confidence interval. Bold text indicates significant associations. DAS28, Disease activity Score of 28 joints; RA, rheumatoid arthritis; HAQ, Health Assessment Questionnaire; VAS, visual analogue scale; MTX, methotrexate; bDMARD, biologic disease-modifying antirheumatic drug. 1 Current treatment 2 Number of previous bDMARDs Conclusion: In this national register study, male sex and limited previous exposure to bDMARDs were independent predictors of reduction of disease activity one year after start of treatment with abatacept for RA, possibly reflecting a better prognosis overall in such patients. Disclosure of Interests: Julia Liukkonen: None declared, Giovanni Cagnotto: None declared, Jan-Åke Nilsson: None declared, Saedis Saevarsdottir: None declared, Carl Turesson Speakers bureau: Abbvie, Bristol Myers-Squibb, Medac, Pfizer, Roche., Consultant of: Roche, Grant/research support from: This study was supported by an unrestricted grant from Bristol-Myers Squibb