Objective To evaluate the precision and construct validity of pediatric Patient Reported Outcomes Measurement Information System® (PROMIS®) instruments in a population of juvenile idiopathic arthritis (JIA) patients and parent proxies. Methods A convenience sample of JIA patients and parents of JIA patients completed PROMIS instruments for eight domains: anger, anxiety, depressive symptoms, fatigue, mobility, pain interference, peer relationships, and upper extremity function. Short form and computerized adaptive test (CAT) scores were derived from item bank responses. Raw scores were translated to standardized T-scores with corresponding standard errors (SEs). Discrimination between inactive versus active disease was evaluated as an indicator of each measures’ construct validity. SEs were plotted to evaluate each instrument’s relative precision. Patient-parent concordance was assessed using intraclass correlations (ICC). Results 228 patients and 223 parents participated, providing 71–78 responses per domain. Patient- and parent-reported anger, fatigue, mobility, and pain interference scores significantly differed between those with inactive and active disease. Anxiety, depressive symptoms, and peer relationships differed by disease activity levels for parent-report only. Short forms and CATs provided comparable reliability to the full item banks across the full range of each outcome. Patient-parent agreement ranged from ICC=0.3 to 0.8. CAT did not reduce the number of items for any domain compared to the short form. Conclusion Precision and discriminatory abilities of PROMIS instruments depend on health domain and report type (self-report versus parent proxy-report) for children with JIA. Varying levels of patient-parent concordance reinforces the importance of considering both perspectives in comprehensive health outcomes assessments.

BackgroundEnthesitis-related arthritis (ERA) is a specific subtype of juvenile idiopathic arthritis (JIA) defined according to the International League of Associations for Rheumatology (ILAR) criteria. We aimed to characterize the clinical features and treatment regimens in an inception cohort of children with ERA.MethodsWe performed a retrospective, cross-sectional, multicenter cohort study including subjects diagnosed with ERA between 1989 and 2012. Patients all fulfilled the ILAR criteria for ERA within 3 months of initial presentation to the rheumatology clinic. Differences in the prevalence of clinical criteria across study sites and by human leukocyte antigen (HLA)-B27 status were assessed using the Wilcoxon rank-sum or chi-square test, as appropriate.ResultsTwo hundred thirty-four children met the inclusion criteria. Their median age at diagnosis was 11.6 years, and 59% were HLA-B27-positive. Sixty-nine percent had enthesitis and arthritis at the time of diagnosis. Seventy-eight percent had a pauciarticular onset. The prevalence of all ILAR criteria at diagnosis, except arthritis and acute anterior uveitis, differed significantly across sites (all p < 0.01). Medication use varied significantly across sites for children with peripheral arthritis (p < 0.001), but not for sacroiliitis or enthesitis only. Nonsteroidal anti-inflammatory drugs and disease-modifying antirheumatic drugs were the most commonly prescribed treatments, with anti-TNF agents primarily being initiation for sacroiliitis. HLA-B27 positivity was associated with male sex, higher active joint count, sacroiliitis, and higher disease activity at disease onset.ConclusionsThe majority of children had a pauciarticular onset, and several statistically significant clinical differences based on HLA-B27 status were identified. The observed heterogeneity in clinical presentation across sites reflects either true differences in patient populations or differences in how the ILAR criteria are being applied.

The SSS was feasible to score and had acceptable reliability for pediatric SIJ MRI evaluation. The ICC improved with additional calibration and reading exercises, even for readers with limited experience.

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Objective Magnetic resonance imaging (MRI) is pivotal in the assessment of early sacroiliitis in children. We aimed to evaluate the agreement between local radiology reports and central imaging reviewers for active inflammation and structural damage at the sacroiliac (SI) joints. Methods Eight hospitals each contributed up to 20 cases of consecutively imaged children and adolescents with juvenile idiopathic arthritis and suspected sacroiliitis. Studies were independently reviewed by 3 experienced musculoskeletal pediatric radiologists. Local assessments of global impression and lesions were coded from the local radiology reports by 2 study team members. Test properties of local reports were calculated using the central imaging team’s majority as the reference standard. Results For 120 evaluable subjects, the median age was 14 years, half of the cases were male, and median disease duration at the time of imaging was 0.8 years (interquartile range 0–2). Sensitivity of local reports for inflammation was high, 93.5% (95% confidence interval [95% CI] 78.6–99.2), and specificity was moderate, 69.7% (95% CI 59.0–79.0), but positive predictive value (PPV) was low, 51.8% (95% CI 38.0–65.3). Twenty‐seven cases (23%) had active inflammation reported locally but rated normal at the central reading, 19 (70%) with subsequent medication changes. The sensitivity of local reports detecting structural damage was low, 45.7% (95% CI 28.8–63.4), and specificity was high, 88.2% (95% CI 79.4–94.2); PPV was low, 61.5% (95% CI 40.6–79.8). Conclusion Substantial variation exists in the interpretation of inflammatory and structural lesions at the SI joints in children. To reliably identify pathology, additional training in the MRI appearance of the maturing SI joint is greatly needed.