FRI0546 TRAJECTORIES OF DISEASE ACTIVITY OVER THE FIRST THREE YEARS FOLLOWING JUVENILE IDIOPATHIC ARTHRITIS DIAGNOSIS
Authors: Stephanie Shoop-Worrall, Kimme Hyrich, Lucy Wedderburn, Wendy Thomson, Nophar Geifman
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> The advent of biological therapies and early aggressive treatment strategies have drastically changed prognoses for children and young people (CYP) with juvenile idiopathic arthritis (JIA). Clinical trials and observational research have demonstrated improvements in disease for the majority, but not all, CYP over time. It is not currently known what the patterns of disease activity are in CYP with JIA and how these cluster over time. <h3>Objectives</h3> To explore latent patterns of clinical juvenile arthritis disease activity scores (cJADAS) following a diagnosis of JIA. <h3>Methods</h3> CYP with JIA were selected if enrolled in the Childhood Arthritis Prospective Study (CAPS), a UK multicentre inception cohort, before January 2015. cJADAS10 scores were calculated based on components (active joint count up to 10, physician global, patient/parent global) collected at diagnosis, six months, one year and then annually to three years. CYP were excluded if no cJADAS10 scores were available within this time frame. Group-based trajectory models were constructed to model latent groups of cJADAS10 scores. Linear, quadratic and cubic polynomials were tested, with one to six trajectories tested within each polynomial group. An optimal model within each polynomial group was selected using Bayesian Information Criteria. The final model was then selected from this shortlist based on model parsimony and clinical plausibility. <h3>Results</h3> Of 1183 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 five cJADAS10 quadratic trajectories (Figure 1): Low-low (59%, initial cJADAS10 median: 6.1), moderate-low (16%, initial cJADAS10 median: 11.5) and three groups with high disease activity at initial presentation (initial median cJADAS10: 17.7 to 19.1). A high-low group experienced the greatest improvement (15%, median improvement 17.2 (IQR 13.7 to 20.1)), and a high-moderate group lesser improvement (5%, median improvement 7.3 (IQR 0.8 to 9.0)). A final high-low-high group experienced improvement to one year followed by disease relapse (5%). <h3>Conclusion</h3> Disease activity in CYP with JIA does not improve in a uniform manner following initial presentation to paediatric rheumatology. Five latent trajectory groups have been identified, with three of these displaying different patterns following initial high disease activity at diagnosis. Identifying distinguishing characteristics for each group may aid the stratification of different treatment strategies to facilitate personalised medicine in JIA. <h3>Acknowledgement</h3> On behalf of CAPS and CLUSTER <h3>Disclosure of Interests</h3> Stephanie Shoop-Worrall Grant/research support from: Your Rheum is funded by the Arthritis Research UK grant 20164, via the Centre for Adolescent Rheumatology at UCL. The event described here was funded by Eli Lilly., Kimme Hyrich Grant/research support from: Grants to institution: BMS, Pfizer, UCB, Lucy Wedderburn: None declared, Wendy Thomson: None declared, Nophar Geifman: None declared