Results from a Canadian cohort study published in Arthritis Care and Research confirm the effectiveness of conventional non-biologic treatment strategies in treating juvenile idiopathic arthritis (JIA).

Investigators abstracted data from the Research in Arthritis in Canadian Children Emphasizing Outcomes study, an inception cohort that recruited children with JIA from 16 Canadian centers between 2005and 2010. Children were followed for ≤5 years, with study visits scheduled at baseline and at 6, 12, 18, 24, 36, 48, and 60 months post-enrollment. Data collected included demographics, clinical information, JIA categories, inflammatory markers, medications, and quality of life measures.

For the present analyses, investigators captured treatment “success” in children, defined as “attainment of inactive disease or maintenance of this state when stepping down treatment.” For children with polyarticular JIA, researchers considered minimally active disease treatment success.

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Study physicians assessed all treatment events independently; they calculated success rates for treatments tried ≥25× in the cohort and performed logistic regression to identify clinical features associated with success.

The investigators observed 1352 participating children in a total of 4429 treatment trials. The median duration of a treatment trial was 7.4 (interquartile range, 3.8-13.7) months. Treatment approaches included nonsteroidal anti-inflammatory drug (NSAID) monotherapy (n=697 trials), NSAID with joint injections (n=447), adding methotrexate to NSAID and/or joint injections (n=566), and adding a biologic medication (n=171).

NSAID monotherapy had a success rate of 54.4% (95% CI, 50.3%-58.6%) and was typically used as initial treatment when <5 joints were involved. The success rate of NSAID monotherapy was greater when the active joint count was <5 (59.5%; 95% CI, 55%-64%).

NSAID plus joint injections had 64.7% success (95% CI, 59.8%-69.7%); adding methotrexate to NSAID and/or joint injections had 60.5% success (95% CI, 55.7%-65.3%).

According to adjusted analyses, a higher number of active joints was strongly associated with lower success rates for NSAID monotherapy (adjusted odds ratio [aOR] 0.9; 95% CI, 0.85-0.94) and for methotrexate combinations (aOR 0.96; 95% CI, 0.94-0.99). Furthermore, each additional year after JIA onset reduced chances of success with methotrexate combinations (aOR 0.83; 95% CI, 0.72-0.95).

These data confirm the validity of existing JIA treatment guidelines; conventional non-biologic treatment strategies were largely effective in achieving treatment targets. Nonetheless, patents with JIA remain a heterogenous group, investigators wrote, and further research is necessary to identify additional characteristics that predict treatment success.

Reference

Chhabra A, Oen K, Huber AM, et al. Real-world effectiveness of common treatment strategies for juvenile idiopathic arthritis: results from a Canadian cohort [published online May 10, 2019]. Arthritis Care Res. doi:10.1002/acr.23922