The purpose of this study is to estimate the retention rate of Abatacept SC over 24 months in routine clinical practice, in rheumatoid arthritis patients, in each country involved in the study. The purpose of the UK substudy is to explore whether integrating self-assessment into routine care could maintain tight control (of inflammation/disease activity) and at potentially lower cost resulting in improved health outcomes and cost-effectiveness.

Inclusion Criteria:

• Patients ≥18 years old at treatment initiation
• Patients diagnosed with established moderate to severe active RA as per the 1987 ACR criteria/2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) Rheumatoid Arthritis Classification Criteria
• Patients naïve of Abatacept IV and who at their physician's discretion are initiated with Abatacept SC. In countries where required (e.g. Germany and Spain), patients naïve of Abatacept IV and who at their physician's discretion have been initiated with Abatacept SC at least 1 month prior to enrollment visit up to 6 months if baseline and disease characteristics data are available
• For Spanish pharmacogenomic sub-study:
• Caucasian patient and from European ancestry
• Patient for whom a collection of blood sample before the initiation of abatacept is possible or available (blood sample was taken in routine practice before the study enrolment)
• Patient who agreed to participate in this substudy and provide a specific signed Pharmacogenomic Blood RNA informed consent
• In the UK, the ART substudy will be proposed to all patients enrolled in ASCORE from amendment approval and application date

Exclusion Criteria:

- Patients who are currently included in any interventional clinical trial in RA

Corhort 1: RA patients naive of Abatacept and any other biologic agents.

Corhort 2: RA patients naïve of Abatacept and who previously failed one or more biologic agents.

In Germany, the study will be proposed to patients using syringe or pre-filled pen devices