Effect of joint hypermobility on outcomes of children with juvenile idiopathic arthritis.

Background: Juvenile idiopathic arthritis (JIA) is common in pediatric rheumatology. Despite treatment, many patients experience persistent disease activity. Joint hypermobility (JH), defined by an excessive range of motion across multiple joints, is prevalent in children and adolescents and may influence disease outcomes in JIA.

Objective: This study examines the impact of JH on symptoms in youth and young adults with JIA.

Methods: Data were obtained from the PR-COIN network and included patients under 21 years old with a diagnosis of JIA. Patients with JIA and JH were matched with those having JIA-only based on age, sex assigned at birth, JIA subtype, and medication exposure. Clinical data, including disease activity measures, patient well-being, and pain ratings, were collected at baseline and follow-up visits.

Results: The sample included 420 patients with JIA + JH and 2100 with JIA only. The JIA + JH group exhibited higher disease activity at baseline, more active arthritis joints, elevated physician global assessment of disease activity scores, and worse patient-reported well-being. These differences persisted over time. The JIA + JH group had a 19-20% greater likelihood of maintaining high disease activity scores and worsening over subsequent visits, indicating a significant impact of JH on disease progression.

Conclusion: JH in youth with JIA is associated with higher and persistent disease activity, suggesting that JH significantly contributes to the disease burden in patients with JIA and should be considered in treatment strategies. Future research should further explore the mechanisms by which JH influences disease activity and investigate comprehensive management approaches to improve outcomes for this population. Key Points • Children with JIA and joint hypermobility (JH) exhibit significantly higher disease activity at baseline compared to those with JIA only, including more active arthritis joints and elevated physician global assessment scores. • The presence of JH in JIA patients is associated with poorer patient-reported well-being and higher overall disease activity scores, which persist over time despite treatment. • JIA + JH patients have a 19-20% greater likelihood of maintaining high disease activity and worsening over subsequent visits, indicating a significant impact of JH on disease progression. • The study suggests that JH should be considered an important clinical factor in the management of JIA, with targeted interventions needed to address the increased disease activity and improve overall patient outcomes.