OBJECTIVES: RF and ACPA are used as diagnostic tools and their presence has been associated with clinical response to some biologic DMARDs (bDMARDs) in RA. This study compared the impact of seropositivity on drug discontinuation and effectiveness of bDMARDs in patients with RA, using head-to-head comparisons in a real-world setting. METHODS: We conducted a pooled analysis of 16 observational RA registries. Inclusion criteria were a diagnosis of RA, initiation of treatment with rituximab (RTX), abatacept (ABA), tocilizumab (TCZ) or TNF inhibitors (TNFis) and available information on RF and/or ACPA status. Drug discontinuation was analysed using Cox regression, including drug, seropositivity, their interaction, adjusting for concomitant and past treatments and patient and disease characteristics and accounting for country and calendar year of bDMARD initiation. Effectiveness was analysed using the Clinical Disease Activity Index evolution over time. RESULTS: Among the 27 583 eligible patients, the association of seropositivity with drug discontinuation differed across bDMARDs (P for interaction <0.001). The adjusted hazard ratios for seropositive compared with seronegative patients were 1.01 (95% CI 0.95, 1.07) for TNFis, 0.89 (0.78, 1.02)] for TCZ, 0.80 (0.72, 0.88) for ABA and 0.70 (0.59, 0.84) for RTX. Adjusted differences in remission and low disease activity rates between seropositive and seronegative patients followed the same pattern, with no difference in TNFis, a small difference in TCZ, a larger difference in ABA and the largest difference in RTX (Lundex remission difference +5.9%, low disease activity difference +11.6%). CONCLUSION: Seropositivity was associated with increased effectiveness of non-TNFi bDMARDs, especially RTX and ABA, but not TNFis.

1st Department of Internal Medicine University of Occupational and Environmental Health Kitakyushu Japan

Center of Rheumatic Diseases University of Medicine and Pharmacy Bucharest Romania

Centre for Epidemiology Versus Arthritis Centre for Musculoskeletal Research University of Manchester Manchester UK

Clinical Epidemiology Karolinska Institutet Stockholm Sweden

Clinical Medicine University of Copenhagen Copenhagen Denmark

DANBIO Registry and Copenhagen Center for Arthritis Research Rigshospitalet Glostrup Denmark

Institut de Recherche en Rhumatologie de Montréal Centre hospitalier de l'Université de Montréal and Université de Montréal Montréal Canada

Italian Group for the Study of Early Arthritis University Hospital of Bari Bari Italy

Rheumatology 5 A Nasonova Research Institute of Rheumatology Moscow Russia

Rheumatology and Clinical Immunology Amsterdam University Medical Centers Amsterdam The Netherlands

Rheumatology Charles University Prague Czech Republic

Rheumatology CHU and University of Montpellier Montpellier France

Rheumatology Clinical University Hospital Santiago de Compostela Spain

Rheumatology Diakonhjemmet Hospital Oslo Norway

Rheumatology Hospital Garcia de Orta Almada Portugal

Rheumatology Karolinska Institutet Stockholm Sweden

Rheumatology Leiden University Medical Center Leiden The Netherlands

Rheumatology Skåne University Hospital Malmö Sweden

Rheumatology Université Paris Sud AP HP Paris France

Rheumatology University Hospital of Strasbourg Strasbourg France

Rheumatology University Hospitals of Geneva Geneva Switzerland

Rheumatology University Medical Centre Ljubljana Ljubljana Slovenia

ROB FIN Registry Helsinki University Hospital and Helsinki University Helsinki Finland

References provided by Crossref.org