Table 2

Characteristics of included studies

Reference	Design	Country of origin	N	Inclusion criteria	Outcome*	Follow up
24	Retrospective	Italy, USA	437	JIA, minimum 4 years FU	1b, 1c, 1e, 1f	>4 years
34	Prospective	Denmark, Finland, Norway, Sweden	440	JIA, population based	1b	8 years
35	Cross-sectional	Taiwan	107	JRA, minimum 1 year FU	1d	?†
36	Prospective	Canada	356	JIA, maximum 6 months FU	1 g, 3a, 4b	6 months
37	Retrospective	Norway	55	JIA, ERA only	1b, 3g	Median 15.3 years (1b), median 23.0 years (3g)
38	Retrospective	USA	104	JIA, RF+ and RF−poly only, minimum 6 mo FU	1a, 1b	>6—>36 months
39	Retrospective	Belgium, Germany, Switzerland, The Netherlands	146	JIA, FU >5 years	1f	5 years
40	Retrospective	Italy	683	JCA, minimum 1 years FU	1h	Mean 10 years
41	Retrospective	Norway	268	JRA	1i, 2a, 3f	Median 14.9 years
42	Retrospective	Germany	171	JCA, JSpA, population based	1i	Mean 7.4 years
43	Prospective	USA	2704	JIA	2c, 3a	?
44	Prospective	Norway	84	JRA and JSpA	2a, 3b	Mean 9.7 years
45‡	Prospective	Sweden	132	JCA, population based	2b, 3d	5 years
46	Retrospective	France	207	JIA, oligo-onset only	2a	6 years
47	Retrospective	Canada	205	JRA, oligo-onset only, minimum 5 years FU	2c, 3c	Median 10.8 years (CHAQ 0–3 years earlier)
48	Retrospective	Canada	181	JRA, minimum 5 years FU, at least 8 years old	2c, 3e	Median >9.2 years (2c), median >11.6 years (3e)
49	Prospective	UK	740	JIA, minimum 1 year FU	3e	>1 year
50‡	Prospective	Sweden	132	JCA, population based	3b, 4a	17 years
51	Cross-sectional	Portugal	114	JIA	3a	Median 3 years†
52	Retrospective	Canada	393	JRA, minimum 5 years FU, at least 8 years old	3a, 3e	Median >11.6 years
53	Retrospective	Italy, USA	227	JRA, maximum 6 months disease duration, minimum 5 years FU	3e, 4d	>5 years
54	Retrospective	Italy	75	JIA, oligo only	3e	>5 years, median >7 years
55	Retrospective	Turkey	67	JRA, minimum 3 years FU	3e	Mean 4.8 years
56	Retrospective	Canada	235	JIA, minimum 6 moths FU	4c	Mean >3.1 years

*1a: Wallace: achievement of CID in first year; 1b: Wallace: achievement of CRM and/or CR during FU; 1c: Wallace: duration first period CID; 1d: Wallace: duration first period CRM; 1e: Wallace: duration of AD before CID; 1f: Wallace: percentage of time spent in AD, CID, CRM and/or CR; 1g: Quasi Wallace: achievement of CID; 1h: Quasi Wallace: achievement of CR during FU; 1i: ACR: percentage of patients in remission at last FU visit; 2a: Dale radiographic classification; 2b: Cassidy radiographic classification; 2c: joint space narrowing, erosions and/or ankylosis on imaging; 3a: (C)HAQ continuous; 3b: (C)HAQ dichotomised >0; 3c: (C)HAQ dichotomised >0.12; 3d: (C)HAQ dichotomised >0.5; 3e: (C)HAQ dichotomised >0.75; 3f: SF-36 continuous; 3g: SF-36 PCS continuous; 4a: SF-36 MCS; 4b: JAQQ continuous; 4c: JAQQ, psychosocial function continuous; 4d: QOLS dichotomised >80.
†Time after diagnosis.
‡These describe the same cohort, but different predictors, outcomes and follow-up.
ACR, American College of Rheumatology; AD, active disease; (C)HAQ, (childhood) health assessment questionnaire; CID, clinical inactive disease; CR, clinical remission off all medications; CRM, clinical remission on medication; ERA, enthesitis-related arthritis; FU, follow-up; JAQQ, juvenile arthritis quality of life questionnaire; JCA, juvenile chronic arthritis, JIA, juvenile idiopathic arthritis; JRA, juvenile rheumatoid arthritis; JSpA, juvenile spondyloarthropathy; MCS, mental component score; oligo, oligoarticular; PCS, physical component score; poly, polyarticular; QOLS, quality of life scales; RF, rheumatoid factor; SF-36, Short Form 36 items.