The vast majority of rheumatoid arthritis (RA) patients in a recent clinical cohort study did not satisfy criteria for participation in biologic agent random controlled trials (RCTs). Eligibility criteria of 30 RCTs of 10 FDA–approved biologic agents to treat RA were reviewed, summarized, and applied to 2 observational clinical cohorts: the Veterans Affairs Rheumatoid Arthritis registry (VARA; n = 1,523) and the Rheumatology and Arthritis Investigational Network Database (RAIN-DB; n = 1,548). Researchers found:

• The mean percentage of patients that satisfied eligibility criteria was 3.7% in RAIN-DB.
• Ineligibility was most often due to low disease activity, specifically low joint counts.
• The mean Disease Activity Score in 28 joints at enrollment was 6.59 (range 6.1–7.1) across RCTs vs 3.87 (0.07–8.69) in VARA and 3.65 (0.49–7.21) in RAIN-DB.
• RCTs for non–tumor necrosis factor (TNF) inhibitor biologic agents were more restrictive than RCTs for TNF inhibitors.