Joint hypermobility and oligoarticular juvenile idiopathic arthritis: What relationship?

Aim: Oligoarticular onset juvenile idiopathic arthritis (oJIA) is characterised by a prevalent lower limb involvement, antinuclear antibodies (ANA) positivity and high risk of anterior uveitis. As we observed that oJIA patients frequently present with joint hypermobility (JH), we investigated whether there was a relationship between oJIA and JH. Methods: Our series consisted of children with oJIA, as defined by the International League of Associations for Rheumatology criteria, for whom complete clinical data of at least 2 years’ duration were available. Clinical and laboratory data, collected at disease onset and at the last follow-up, included: sex, age, presence of JH according to the Beighton score, disease activity, presence of uveitis, ANA, treatment and outcome. Results: A total of 274 oligoarticular JIA patients (224 female, 50 male; mean age: 11.5) followed on average for 6.6 years, entered the study. The mean age at disease onset was 4.9 years, ANA were positive in 83.9% and uveitis occurred in 20.8%. JH was present in 70.8% of cases at onset, in 44.5% at the last evaluation. JH was more frequent in females (73.7%) than in males (58.0%) (P = 0.028). Uveitis was less frequent in hypermobile children both at diagnosis (17.5 vs. 28.7%, P = 0.037) and during overall disease course (23.7 vs. 36.3%, P = 0.034). Of 163 subjects with at least 5-year follow-up, the full clinical remission rate was significantly higher in JH patients (50.5%) than in those without JH (42.3%; P = 0.042). Conclusion: In patients with oligoarticular JIA, JH is more frequent than in healthy subjects, uveitis less frequent and the long-term outcome better.