Table 2 Baseline characteristics of children in the study sample

No. of children

26

13

13

Girls

14 (54%)

9 (69%)

5 (39%)

.24^a

Age at MRI in years

14.3 (11.2–16.5)

14.0 (9.8–17.0)

14.4 (11.6–15.7)

.78^b

JIA ILAR subtype

Oligoarthritis; persistent

16 (62%)

9 (69%)

7 (54%)

.69^a

Oligoarthritis; extended

2 (8%)

1 (8%)

1 (9%)

> .99^a

Polyarthritis; RF negative

7 (27%)

3 (23%)

4 (31%)

> .99^a

Enthesitis-related arthritis

1 (4%)

0 (0%)

1 (8%)

> .99^a

No. of clinically inflamed joints

1.0 (1.0–2.0)

1.0 (1.0–1.5)

2.0 (1.0–3.0)

.16^b

No. of joints with limited range of motion

1.0 (0.0–2.0)

1.0 (1.0–1.5)

1.0 (0.5– 2.0)

.40^b

Physician's global assessment of overall disease activity^c

13.5 (5.0–17.8)

15.0 (5.0–19.0)

10.0 (1.5–15.0)

.15^b

CRP, mg/l

0.5 (0.3–1.7)

1.3 (0.4–2.5)

0.3 (0.2–0.5)

.08^b

ESR, mm/h

2.0 (2.0–8.5)

8.0 (2.0–11.5)

2.0 (2.0–2.8)

.08^b

Drug treatment

No medication

14 (54%)

7 (54%)

7 (54%)

> .99^a

NSAIDs

6 (23%)

3 (23%)

3 (23%)

> .99^a

MTX or other cDMARD

4 (15%)

2 (15%)

2 (15%)

> .99^a

bDMARD

2 (8%)

1 (8%)

1 (8%)

> .99^a