Table 1 Demographic characteristics of the study population

Age (year): mean (SD)

11.4 (2.0)

12.0 (1.4)

Z = −0.82

0.41

Gender (female)

8 (89 %)

7 (70 %)

χ ²(1) = 0.20

0.66

JIA categories:

χ ²(6) = 6.83

0.34

 Systemic arthritis

1 (11 %)

1 (10 %)

 Oligoarthritis persistent

2 (22 %)

4 (40 %)

 Oligoarthritis extended

2 (22 %)

0 (0 %)

 Polyarthritis (RF-negative)

2 (22 %)

3 (30 %)

 Polyarthritis (RF-positive)

0 (0 %)

1 (10 %)

 Psoriatic arthritis

2 (22 %)

0 (0 %)

 Enthesitis-related arthritis

0 (0 %)

1 (10 %)

Time from onset to diagnosis (year): mean(SD)^a

0.7 (0.8)

0.8 (0.7)

Z = −0.53

0.60

Disease duration(year): mean(SD)^b

5.1 (4.0)

7.6 (4.0)

Z = −1.47

0.14

Current use of medication:

 Methotrexate use

4 (44 %)

3 (30 %)

χ ²(1) = 0.43

0.52

 Etanercept use

3 (33 %)

4 (40 %)

χ ²(1) = 0.09

0.76

Treatment time with methotrexate (year): mean(SD)

0.9 (1.4)

0.9 (1.3)

Z = −0.05

0.97

Treatment time with etanercept (year): mean(SD)

0.5 (1.0)

1.4 (2.9)

Z = −2.01

0.91