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 (RF), positive anti-cyclic citrullinated peptide (CCP) antibodies, joint damage.
Moderate/High Disease Activity†	Clinical Juvenile Disease Activity Score based on 10-joints (cJADAS-10) > 2.5†
Low Disease Activity†	Clinical Juvenile Disease Activity Score based on 10-joints (cJADAS-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 MRI findings consistent with sacroiliitis along with clinical examination findings consistent with sacroiliitis (e.g. pain with direct palpation of the SI 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 treating provider.

^*JIA = juvenile idiopathic arthritis; ILAR = International League Against Rheumatism.

^†The cJADAS-10 was used to define low disease activity (≤ 2.5 and ≥ 1 active joint) versus high/moderate disease activity (> 2.5). While this is provided as a general parameter, the cJADAS-10 should be interpreted within the clinical context.