Objective: To explore the parent and child acceptable symptom state in juvenile arthritis (JA-PASS and JA-CASS, respectively) and estimate the JA-PASS and JA-CASS cutoff values for outcome measures.
Methods: Children with juvenile idiopathic arthritis (JIA) and their parents completed a multi-dimensional questionnaire that included parent-reported and child-reported outcomes and a question about whether they considered the disease state as satisfactory. Additional assessments included demographic data, physician-reported outcomes, and acute-phase reactant levels. Stepwise logistic regression was used to assess contributors to JA-PASS and JA-CASS. Cutoff values of outcome measures that defined JA-PASS and JA-CASS were determined using both 75th percentile and receiver-operating characteristic (ROC) curve methods. Testing procedures included evaluation of discriminative and construct validity of the satisfaction question and assessment of reliability of JA-PASS and JA-PASS cutoffs.
Results: Of 584 parents, 385 (65.9%) considered their child in JA-PASS. Of 343 children, 236 (68.8%) considered themselves in JA-CASS. Significant contributors to being in either JA-PASS or JA-CASS were absence of active joints, better rating of overall well-being, and better physical function or health. Cutoff values yielded by 75th percentile and ROC curve methods were similar. Parent, child, and physician global ratings yielded the lowest percentage of false-positive misclassification and the best tradeoff between sensitivity and specificity. The satisfaction question showed good discriminative and construct validity and the JA-PASS and JA-PASS cutoffs were found to be stable over time.
Conclusion: The acceptable symptom state is a relevant concept for children with JIA and their parents and constitutes a valid outcome measure that is potentially applicable in routine practice and clinical trials.