Long term outcomes following achievement of clinically inactive disease in juvenile idiopathic arthritis: the importance of definition.

Background: Potential targets for treat-to-target strategies in JIA are minimal disease activity (MDA) and clinically inactive disease (CID). Short and long-term outcomes following achievement of MDA and CID on the cJADAS10 and CID on Wallace’s preliminary criteria were compared.

Methods: Children recruited to the Childhood Arthritis Prospective Study, a UK multicentre inception cohort, were selected if recruited prior to January 2011 and diagnosed with oligoarthritis or rheumatoid factor negative or positive polyarthritis.
At one year following diagnosis, children were assessed for MDA on the cJADAS10 and CID on both Wallace’s preliminary criteria and the cJADAS10. Associations were tested between these disease states and i) functional ability, ii) absence of limited joints, iii) psychosocial health and v) pain at one year and annually to five years.

Results: Of 832 children, 70% were female and the majority had oligoarthritis (68%). At one year, 21% had achieved CID according to both definitions, 7% on Wallace’s preliminary criteria only, 16% on cJADAS10 only and 56% on neither. Only 10% of children in the entire cohort achieved MDA without also having CID.
Achieving either early CID state was associated with greater absence of limited joints. However, only CID on cJADAS10 was associated with improved functional ability and psychosocial health. Achieving CID was superior to MDA in terms of short and long-term pain and the absence of limited joints.

Conclusion: CID on the cJADAS10 may be a preferable treatment target to CID on Wallace’s preliminary criteria in terms of both feasibility of application and long-term outcomes.