Table 1 Demographic, clinical, and laboratory characteristics of JRA patients, according to disease onset subtype

Polyarthritis (n = 67)

Oligoarthritis (n = 151)

Demographic variables

   Males (n [%])

59 (27%)

19 (28%)

40 (27%)

0.87

   Age (years) at onset

8.0 (3.7 to 11.6)

9.4 (5.5 to 12.9)

7.3 (3.1 to 11.5)

<0.01

   Disease duration (years) at follow up

14.8 (13.6 to 16.2)

14.6 (13.4 to 16.3)

15.0 (13.8 to 16.2)

0.68

Clinical variables

   Number of cumulative affected joints

5 (2 to 15)

20 (11 to 34)

4 (2 to 6)

<0.01

   Arthritis severity index

2 (0 to 11)

12 (2 to 37)

2 (0 to 5)

<0.01

   Physician global assessment

1 (1 to 2)

2 (1 to 3)

1 (1 to 2)

<0.01

   Childhood Health Assessment Questionnaire score

0 (0 to 0.4)

0.1 (0 to 0.6)

0 (0 to 0.3)

<0.01

   Patients with uveitis (n [%])

42 (19%)

10 (15%)

34 (23%)

0.27

   Remission status at follow-up (n [%])

Current remission

122 (56%)

32 (48%)

90 (60%)

<0.01

Active but previous remission

55 (25%)

14 (21%)

41 (27%)

Continuously active

41 (19%)

21 (31%)

20 (13%)

   Radiographic erosions grade III to IV (n [%])

51 (23%)

30 (45%)

21 (14%)

<0.01

Laboratory variables

   Erythrocyte sedimentation rate (mm/hour)

6 (4 to 13)

7 (4 to 22)

6 (4 to 11)

0.19

   C-reactive protein (mg/l)

5 (3 to 6)

5 (3 to 14)

5 (1 to 5)

<0.01

   Antinuclear antibody positivity

79 (36%)

17 (26%)

62 (41%)

0.03

   IgM-rheumatoid factor positivity

11 (5%)

11 (16%)

0 (0%)

<0.01