Abstract
Abstract
Background
Composite disease scores in juvenile idiopathic arthritis (JIA), such as the clinical Juvenile Arthritis Disease Activity Score (cJADAS), include multiple disease manifestations, presented as a single score. These overall scores aid understanding of disease holistically in each child or young person (CYP), and have been suggested as outcomes for clinical trials and targets in treat to target clinical strategies. However, signs and symptoms of disease may not follow similar patterns following a JIA diagnosis. It is not currently known what the patterns of disease activity are in CYP with JIA and how these cluster over time.
Methods
CYP with JIA were selected if enrolled in the Childhood Arthritis Prospective Study (CAPS), a UK multicentre inception cohort, before January 2015. cJADAS10 components (active joint count 0-10, physician global, patient/parent global) were collected at diagnosis, six months, one year and then annually to three years.
Multivariate group-based trajectory models modelled cJADAS10 component scores using censored-normal (physician and parent global) and zero-inflated Poisson (active joint count) distributions. Within linear, quadratic and cubic polynomials, one to ten trajectories were tested. The optimal models were selected using Bayesian Information Criteria, model parsimony and clinical plausibility.
Results
Of 1,183 CYP selected, the majority were female (65%) and of white ethnicity (90%) with oligoarticular JIA the most common JIA category (45%).
The optimal model identified six multivariate patterns of disease. In four of these clusters, signs and symptoms of disease had similar patterns over time: Low-Remission (32%), Low-Low (20%), High-Low (16%) and High-Low-High (10%). However, in two groups, Low-Chronic (14%) and High Chronic (8%), manifestations of inflammation and wellbeing followed different trajectory severities and shapes over time. These groups demonstrated persistent poor wellbeing despite control of inflammatory signs.
Conclusion
Disease activity in CYP with JIA does not improve in a uniform manner following initial presentation to paediatric rheumatology. Six latent multivariate trajectories have been identified in young people with JIA, two of which persist with chronic poor wellbeing despite lowered inflammation.
Conflicts of Interest
The authors declare no conflicts of interest.