Table 1.

Terms and definitions^*

Term	Definition
Polyarthritis population	Children with JIA and non-systemic polyarthritis (≥5 joints ever involved); may include children from ILAR JIA categories of polyarticular (rheumatoid factor positive or negative), extended oligoarticular, enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis.
Risk factors	One or more of the following: positive rheumatoid factor, positive anti–cyclic citrullinated peptide antibodies, joint damage.
Moderate/high disease activity	Clinical Juvenile Disease Activity Score based on the cJADAS-10 >2.5.
Low disease activity	Clinical JADAS-10 ≤2.5 and ≥1 active joint.
Sacroiliitis population	Patients with active sacroiliitis who will most likely be classified within the ILAR categories of enthesitis- related arthritis, psoriatic arthritis, and undifferentiated arthritis, but may include patients in any of the ILAR JIA categories.
Active sacroiliitis	Prior or current magnetic resonance imaging findings consistent with sacroiliitis along with clinical examination findings consistent with sacroiliitis (e.g., pain with direct palpation of the sacroiliac joints) and/or patient-reported symptoms of inflammatory back pain.
Enthesitis population	Patients with enthesitis (tendon-to-bone insertion sites) who will most likely be from the ILAR categories of enthesitis-related arthritis, psoriatic arthritis, and undifferentiated arthritis, but may include patients from any of the ILAR JIA categories.
Active enthesitis	Tenderness and/or swelling of the entheses determined to require medical treatment per the treatment provider.

^*Disease activity (moderate/high and low) as defined by the clinical Juvenile Disease Activity Score based on 10 joints (cJADAS-10) is provided as a general parameter and should be interpreted within the clinical context. JIA = juvenile idiopathic arthritis. ILAR = International League of Associations for Rheumatology.