Abstract Background/Aims Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease in children, associated with reduced functional ability and quality of life, as well as negative mental health outcomes. The condition is known to persist into adulthood, but the proportion of individuals impacted has not been systematically reviewed. The objectives of this systematic review were to: identify the proportion of children with JIA that continue to have (a) active disease, (b) limited functional ability, and (c) impacted mental health in adulthood, and to (d) describe the impact of JIA on quality of life in adulthood compared to non-JIA peers. Methods Searches were conducted on 9-August-2025 in MEDLINE, Embase and PubMed. Observational studies that measured persistent disease activity, functional ability, mental health, and quality of life in adults ≥18 years with JIA were included. Studies investigating outcomes in any ILAR category were included. There were no restrictions on context, setting, publication date, or number of participants. Risk of bias was assessed using the modified Quality In Prognosis Studies (QUIPS) tool. Results Forty-four studies published 1968-2024 were included. Sample sizes ranged from 20-2,592 participants, average age of study participants at last follow-up ranged from 18-43 years. Global representation was limited: 32 (73%) studies were conducted in Europe, and 7 (16%) in North America. Overall, risk of bias was deemed to be moderate to high. Persistent arthritis: twenty-six studies reported persistent active disease in adults with JIA. At last follow-up: 33-66% patients had active disease, 6-63% were in remission off-medication, and 64-71% continued using specialist healthcare services beyond age 18. Functional ability: nineteen studies reported functional ability in adults with JIA. According to Steinbrocker criteria and (Childhood) Health Assessment Questionnaire scores, between 32-76% and 28-90% patients had limited functional ability in adulthood, respectively. Mental health: eleven studies reported mental health outcomes in adults with JIA, suggesting up to 7% of adults with JIA may have a mental health diagnosis (anxiety or depression). Studies using non-diagnostic outcome measures found presence of mental health difficulties in up to 38% of patients. Quality of life: fourteen studies compared quality of life between adults with JIA and non-JIA comparators. All found those with JIA to have worse quality of life scores in ≥ 1 physical-health related domain. Ten studies found those with JIA to have worse quality of life scores in ≥ 1 mental-wellbeing related domain. Conclusion This systematic literature review found many studies of outcomes in adults with JIA, although sample size and age range varied. Overall, it was evident that many adults with JIA had persistent active disease, limited functional ability, and mental health problems. Physical health-related quality of life appeared to be worse in adults with JIA compared with non-JIA comparators. Disclosure J. Rawlinson-Smith: None. R. Keerio: None. J.H. Humphreys: None. K.L. Hyrich: None. L. Kearsley-Fleet: None.
Rawlinson-Smith et al. (2026) studied this question.