The purpose of this study is to compare the incidence rates of infection among patients with rheumatoid arthritis who are treated with abatacept and those who are treated with other anti-rheumatic medications

Inclusion Criteria:

• Diagnosis of rheumatoid arthritis
• Claims indicating infusion, injection, or dispensing of abatacept, a DMARD, or a BDM
• Age 18 years or older at the time of drug initiation
• Enrollment in the health plan at least 6 continuous months leading up to the time of study drug initiation

Exclusion Criteria:

• Below 18 years of age at the time of BDM or DMARD initiation
• Lacking six months of continuous enrollment prior to the initiation of one of the study drugs

United Healthcare