OBJECTIVE: To investigate the role of rheumatoid factor (RF) status and anti-citrullinated peptide antibody (ACPA) status as predictors of abatacept (ABA) effectiveness in patients with rheumatoid arthritis (RA). METHODS: We conducted a pooled analysis of data from 9 observational RA registries in Europe (ARTIS [Sweden], ATTRA [Czech Republic], BIOBADASER [Spain], DANBIO [Denmark], GISEA [Italy], NOR-DMARD [Norway], ORA [France], Reuma.pt [Portugal], and SCQM-RA [Switzerland]). Inclusion criteria were a diagnosis of RA, initiation of ABA treatment, and available information on RF and/or ACPA status. The primary end point was continuation of ABA treatment. Secondary end points were ABA discontinuation for ineffectiveness or adverse events and response rates at 1 year (good or moderate response according to the European League Against Rheumatism criteria with LUNDEX adjustment for treatment continuation). Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the study end points in relation to RF and ACPA status were calculated. RESULTS: We identified 2,942 patients with available data on RA-associated autoantibodies; data on RF status were available for 2,787 patients (77.0% of whom were RF positive), and data on ACPA status were available for 1,903 patients (71.3% of whom were ACPA positive). Even after adjustment for sociodemographic and disease- and treatment-related confounders, RF and ACPA positivity were each associated with a lower risk of ABA discontinuation for any reason (HR 0.79 [95% CI 0.69-0.90], P < 0.001 and HR 0.78 [95% CI 0.68-0.90], P < 0.001, respectively), compared to RF-negative and ACPA-negative patients. Similar associations with RF and ACPA were observed for discontinuation of ABA treatment due to ineffectiveness, with HRs of 0.72 (95% CI 0.61-0.84) and 0.74 (95% CI 0.62-0.88), respectively (both P < 0.001). CONCLUSION: Our results strongly suggest that positivity for RF or ACPA is associated with better effectiveness of ABA therapy.

DANBIO Registry and University of Copenhagen Copenhagen Denmark and Rigshospitalet Glostrup Denmark

Diakonhjemmet Hospital Oslo Norway

Hospital Clinic of Barcelona and IDIBAPS Barcelona Spain

Institute of Rheumatology and University Hospital Prague Czech Republic

Lund University and Skåne University Hospital Malmö Sweden

Strasbourg University Hospital and University of Strasbourg CNRS Institut de Biologie Moléculaire et Cellulaire Immunopathologie et Chimie Thérapeutique Strasbourg France

Université Paris Sud Hôpitaux Universitaires Paris Sud Hôpital Bicêtre AP HP and INSERM U1184 Le Kremlin Bicêtre France

University of Bari and University Hospital Bari Italy

University of Geneva and University Hospital of Geneva Geneva Switzerland

University of Lisbon and Santa Maria Hospital Lisbon Portugal

References provided by Crossref.org

Imputing missing data of function and disease activity in rheumatoid arthritis registers: what is the best technique?

Body mass does not impact the clinical response to intravenous abatacept in patients with rheumatoid arthritis. Analysis from the "pan-European registry collaboration for abatacept (PANABA)

Rheumatoid Arthritis Patients after Initiation of a New Biologic Agent: Trajectories of Disease Activity in a Large Multinational Cohort Study