Table 1

Sociodemographic and disease-related characteristics of the JIA subgroups

TotalPersistent oligoarthritisExtended oligoarthritisRF-positive polyarthritisRF-negative polyarthritisSystemicEnthesitis-related arthritisPsoriatic arthritisUndifferentiated arthritis
Patients (N/%)585 (100)105 (17.9)78 (13.3)68 (11.6)99 (16.9)56 (9.6)110 (18.8)19 (3.3)54 (9.2)
Female (N/%)385 (65.8)77 (73.3)55 (70.5)62 (91.2)66 (68.0)33 (58.9)41 (38,0)14 (73.7)34 (63.0)
Age at disease onset (years; median(Q1; Q3))9.9 (5.1; 13.7)7.6 (2.9; 11)5.2 (2.1; 9.4)11.2 (7.8; 13.4)8.7 (3.9; 13)6.9 (4.1; 11.9)12.5 (10.1; 15)10.4 (6.4; 13.4)13.9
(11.5; 15)
Age at diagnosis (years; median(Q1; Q3))12 (6.9; 16)8.3 (3.5; 11.9)7 (3; 13.8)12.2 (9.1; 15.2)11.8 (7.2; 16)7.1 (4.6; 14.3)15.1 (12.7; 17)12.8 (8.5; 15.5)18 (14.7; 25.4)
Age at the time of last visit (years; median(Q1; Q3))28.6 (21.8; 38.6)22.3 (20.2; 29.1)25.95 (21.1; 36.2)35.3 (24.9; 42.7)29.2 (22.3; 38.4)30.15 (24.45; 38.3)28.2 (21.7; 39.5)24.5 (20.6; 32.9)47.4 (37.7; 53.9)
Disease duration (years; median(Q1; Q3))20.2 (12.8; 29.6)16.6 (12.43; 23)20 (16.5; 27.9)24.1 (12.8; 33.6)21.5 (12.9; 30.7)22.7 (14.8; 30.2)15.8 (9.4; 26.7)14.9 (9.1; 24.2)34.3 (25.4; 43.7)
ANA + (N/%)141 (33.652 (54.7)28 (45.2)16 (31.4)18 (23.7)6 (15.4)11 (18.3)7 (41.2)3 (17.7)
RF + (N/%)81 (17.3)3 (3.5)7 (10)58 (92.1)0 (0)0 (0)0 (0)2 (11.8)11 (32.3)
ACPA + (N/%)52 (19.6)2 (5)4 (12.1)37 (72.5)3 (5)0 (0)0 (0)1 (10)5 (22.7)
HLA B27 + (N/%)103 (26.53 (5.9)4 (8.5)1 (1,9)3 (5.3)1 (3)81 (81.8)3 (21.4)7 (19.4)
Years of education (median(Q1; Q3))12 (9; 15)12 (11.5; 15.5)12 (9; 12)12 (12; 15)12 (9; 12)12 (11; 17)12 (9; 15)12 (6; 16)12 (9; 15)
Professional situation
Employed266 (78.7%)37 (94.9%)29 (76.3%)34 (77.3%)51 (77.3%)24 (88.9%)55 (73.3%)6 (66.7%)28 (73.7%)
Unemployed30 (8.8%)2 (5.1%)2 (5.3%)3 (6.8%)8 (12.1%)2 (7.4%)10 (13.3%)2 (22.2%)1 (2.6%)
Retired13 (3.8%)0 (0%)1 (2.6%)4 (9.1%)3 (4.5%)0 (0%)2 (2.7%)0 (0%)3 (7.9%)
Retired due to JIA disability29 (8.6%)0 (0%)6 (15.8%)3 (6.8%)4 (6.1%)1 (3.7%)8 (10.7%)1 (11.1%)6 (15.8%)
Disease activity
Active (N/%)171 (37.7)20 (25)23 (38.3)23 (51.1)30 (40.5)26 (47.3)28 (34.2)2 (16.7)19 (44.2)
Inactive (N/%)282 (62.3)60 (75)37 (61.7)22 (48.9)44 (59.5)29 (52.7)54 (65.9)10 (83.3)24 (55.8)
JADI-A (median(Q1; Q3))0 (0; 6)0 (0; 0)1 (0; 7)2.5 (0; 24)4 (0; 13)6 (0; 20)0 (0; 0)0 (0; 0)29 (29; 29)
JADI-E (median(Q1; Q3))0 (0; 0)0 (0; 0)0 (0; 0)0 (0; 0)0 (0; 1)0 (0; 2)0 (0; 0)0 (0; 0)4 (4; 4)
Past treatment
Corticosteroids (N/%)233 (39.8)21 (20.2)23 (29.5)54 (79.4)39 (39.4)35 (62.5)28 (26.2)4 (21.1)27 (55.1)
Synthetic DMARDs (N/%)469 (80.2)74 (71.2)65 (83.3)64 (94.1)88 (88.9)46 (82.1)67 (62.6)17 (89.5)43 (87.8)
Biological DMARDs (N/%)269 (46)19 (18.3)32 (41)47 (69.1)38 (38.4)26 (46.4)56 (52.3)8 (42.1)39 (79.6)
Current treatment
Corticosteroids (N/%)135 (23.1)8 (7.7)13 (16.7)34 (50)25 (25.3)20 (35.7)11 (10.3)2 (10.5)21 (42.9)
Synthetic DMARDs (N/%)302 (51.6)47 (45.2)43 (55.1)43 (63.2)56 (56.6)26 (46.4)37 (34.6)10 (52.6)35 (71.4)
Biological DMARDs
(N/%)
208 (35.9)17 (16.4)23 (29.5)38 (55.9)29 (29.3)19 (33.9)44 (41.1)6 (31.6)32 (65.3)
  • Sample size is not constant due to missing data:.

  • Age at diagnosis: total n=553; persistent oligoarthritis n=100; extended oligoarthritis n=74; RF positive polyarthritis n=65; RF negative polyarthritis n=91; systemic n=51 enthesitis-related arthritis n=101; psoriatic arthritis n=18; undifferentiated arthritis n=49.

  • ANA: total n=419; persistent oligoarthritis n=95; extended oligoarthritis n=62; RF positive polyarthritis n=51; RF negative polyarthritis n=76;systemic n=39; enthesitis-related arthritis n=60; psoriatic arthritis n=17; undifferentiated arthritis n=19

  • RF: total n=469; persistent oligoarthritis n=86; extended oligoarthritis n=70; RF positive polyarthritis n=63; RF negative polyarthritis n=93; systemic n=41; enthesitis-related arthritis n=65; psoriatic arthritis n=17; undifferentiated arthritis n=34

  • ACPA: total n=264; persistent oligoarthritis n=40; extended oligoarthritis n=33; RF positive polyarthritis n=51; RF negative polyarthritis n=60; systemic n=21; enthesitis-related arthritis n=27; psoriatic arthritis n=10; undifferentiated arthritis n=22

  • HLA B27: total n=264; persistent oligoarthritis n=40; extended oligoarthritis n=33; RF positive polyarthritis n=51; RF negative polyarthritis n=60; systemic n=21; enthesitis-related arthritis n=27; psoriatic arthritis n=10; undifferentiated arthritis n=22.

  • Years of education: total n=317; persistent oligoarthritis n=36; extended oligoarthritis n=39; RF positive polyarthritis n=37; RF negative polyarthritis n=63; systemic n=27; enthesitis-related arthritis n=70; psoriatic arthritis n=10; undifferentiated arthritis n=33.

  • Professional situation: total n=338; persistent oligoarthritis n=39; extended oligoarthritis n=38; RF positive polyarthritis n=44; RF negative polyarthritis n=66; systemic n=27; enthesitis-related arthritis n=75; psoriatic arthritis n=10; undifferentiated arthritis n=38.

  • Disease activity: total n=453; persistent oligoarthritis n=80; extended oligoarthritis n=60; RF positive polyarthritis n=45; RF negative polyarthritis n=74; systemic n=55; enthesitis-related arthritis n=82; psoriatic arthritis n=12; undifferentiated arthritis n=43.

  • JADI-A/JADI-E: total n=190/186; persistent oligoarthritis n=36/33; extended oligoarthritis n=32/29; RF positive polyarthritis n=22/24; RF negative polyarthritis n=39/38; systemic n=21/20; enthesitis-related arthritis n=33/35; psoriatic arthritis n=6/6; undifferentiated arthritis n=1/1.

  • .ACPA, anti-citrullinated protein antibodies; ANA, antinuclear antibodies; DMARD, disease-modifying antirheumatic drugs; HAQ, Health Assessment Questionnaire; JADI-A, Juvenile Arthritis Damage Index—articular; JADI-E, Juvenile Arthritis Damage Index—extra-articular; JIA, juvenile idiopathic arthritis; RF, rheumatoid factor.