Relationship of Fatigue, Pain Interference, and Physical Disability in Children Newly Diagnosed With Juvenile Idiopathic Arthritis.

OBJECTIVE: Our objectives were to quantify the relationships among fatigue, pain interference, and physical disability in children with juvenile idiopathic arthritis (JIA) and to test whether fatigue mediates the relationship between pain interference and physical disability in JIA. METHODS: Patients enrolled within three months of JIA diagnosis in the Canadian Alliance of Pediatric Rheumatology Investigators (CAPRI) Registry between February 2017 and May 2023 were included. Their parents completed the Patient-Reported Outcomes Measurement Information System fatigue and pain interference short proxy questionnaires and the Childhood Health Assessment Questionnaire disability index at registry enrollment. Associations were assessed using Pearson correlations and multiple linear regression. Structural equation modeling (SEM) was used to test if fatigue mediates the relationship between pain interference and physical disability. RESULTS: Among 855 patients (61.4% female, 44.1% with oligoarthritis), most reported fatigue and pain interference scores similar to those in the reference population, but 15.6% reported severe fatigue and 7.3% reported severe pain interference, with wide variation across JIA categories. Fatigue was strongly correlated with pain interference (r = 0.72, P < 0.001) and with physical disability (r = 0.60, P < 0.001). Pain interference (ß = 0.027, P < 0.001) and fatigue (ß = 0.013, P < 0.001) were both associated with physical disability after controlling for each other and potential confounders. SEM supported our hypothesis that fatigue partially mediates the relationship between pain interference and physical disability. CONCLUSION: Our findings suggest both fatigue and pain interference are independently associated with physical disability in children newly diagnosed with JIA, and the effect of pain interference may be partly mediated by fatigue.

Reliability assessment of the OMERACT whole-body magnetic resonance imaging scoring system for juvenile idiopathic arthritis.

Inter-reader reliability of a new scoring system for evaluating joint inflammation and enthesitis in whole body MRI (WBMRI) in juvenile idiopathic arthritis was tested. The scoring system grades 732 item-region combinations of bone marrow and soft tissue changes for commonly involved joints and entheseal sites. Five radiologists rated 17 WBMRI scans through an online rating platform. Item-wise reliability was calculated for 117 items with non-zero scores in >10 % of readings. Interquartile ranges of the five-reader Kappa reliability coefficients were 0.58-0.73 (range: 0.36-0.88) for the joints, 0.65-0.81 (range: 0.39-0.95) for the entheses, and 0.62-0.75 (range: 0.60-0.76) for chronic nonbacterial osteomyelitis-like lesions.

Predictors of persisting pain in children with Juvenile Idiopathic Arthritis: a case control study nested in the ReACCh-Out cohort.

BACKGROUND: To identify baseline predictors of persisting pain in children with Juvenile Idiopathic Arthritis (JIA), relative to patients with JIA who had similar baseline levels of pain but in whom the pain did not persist. METHODS: We used data from the Research in Arthritis in Canadian Children emphasizing Outcomes (ReACCh-Out) inception cohort to compare cases of 'moderate persisting pain' with controls of 'moderate decreasing pain'. Moderate pain was defined as a Visual Analogue Scale (VAS) for pain measurement score of > 3.5 cm. Follow-up was minimum 3 years. Univariate and Multivariate logistic regression models ascertained baseline predictors of persisting pain. RESULTS: A total of 31 cases and 118 controls were included. Mean pain scores at baseline were 6.4 (SD 1.6) for cases and 5.9 (1.5) for controls. A greater proportion of cases than controls were females (77.4% vs 65.0%) with rheumatoid factor positive polyarthritis (12.9% vs 4.2%) or undifferentiated JIA (22.6% vs 8.5%). Oligoarthritis was less frequent in cases than controls (9.7% vs 33%). At baseline, cases had more active joints (mean of 11.4 vs 7.7) and more sites of enthesitis (4.6 vs 0.7) than controls. In the final multivariate regression model, enthesitis count at baseline (OR 1.40, CI 95% 1.19-1.76), female sex (4.14, 1.33-16.83), and the overall Quality of My Life (QoML) baseline score (0.82, 0.69-0.98) predicted development of persisting pain. CONCLUSIONS: Among newly diagnosed children with JIA with moderate pain, female sex, lower overall quality of life, and higher enthesitis counts at baseline predicted development of persisting pain. If our findings are confirmed, patients with these characteristics may be candidates for interventions to prevent development of chronic pain.

Determination of Relative Weightings for Sacroiliac Joint Pathologies in the OMERACT Juvenile Arthritis Magnetic Resonance Imaging Sacroiliac Joint Score.

This study aims to determine the relative weights (point value) of items of the juvenile idiopathic arthritis magnetic resonance imaging-sacroiliac joint scoring system (JAMRIS-SIJ). An adaptive multicriteria decision analysis was performed using the 1000Minds web application to determine the relative weights of the items in the JAMRIS-SIJ inflammation and damage domains. Experts in imaging and rheumatology independently completed a conjoint analysis survey (CAS) to determine the point value of the measurement items of the JAMRIS-SIJ. Each CAS survey question asked the expert to compare two hypothetical patient profiles, which were otherwise similar but different at two items at a time, and to select which item showed a more severe stage of inflammation or osteochondral damage. In addition, experts ranked 14 JAMRIS-SIJ grade only or image + grade patient vignettes while blinded to the CAS-derived weights. The validity of the weighted JAMRIS-SIJ was tested by comparing the expert CAS-weighted score and the image + grade ranking method. Seventeen experts completed the CAS (11 radiologists and 6 rheumatologists). Considering the point value for inflammation domain items, osteitis (24.7%) and bone marrow edema (24.3%) had higher group-averaged percentage weights compared to inflammation in erosion cavity (16.9%), joint space enhancement (13.1%), joint space fluid (9.1%), capsulitis (7.3%), and enthesitis (4.6%). Similarly, concerning the damage domain, ankylosis (41.3%) and erosion (25.1%) showed higher group-averaged weights compared to backfill (13.9%), sclerosis (10.7%), and fat metaplasia lesion (9.1%). The Spearman correlation coefficients of the CAS-weighted vignette order and unweighted JAMRIS-SIJ grade only order vignettes for all experts were 0.79 for inflammation and 0.80 for damage. The correlations of image vignettes among imaging experts to CAS were 0.75 for inflammation and 0.90 for damage. The multicriteria decision analysis identified differences in relative weights among the JAMRIS-SIJ measurement items. The determination of the relative weights provided expert-driven score scaling and face validity for the JAMRIS-SIJ, enabling the future evaluation of its longitudinal construct validity.

CanVasc consensus recommendations for the use of avacopan in antineutrophil cytoplasm antibody-associated vasculitis: 2022 addendum.

OBJECTIVE: In 2020, the Canadian Vasculitis Research Network (CanVasc) published their updated recommendations for the management of ANCA-associated vasculitides (AAV). The current addendum provides further recommendations regarding the use of avacopan in AAV based on a review of newly available evidence. METHODS: An updated systematic literature review on avacopan (formerly, CCX168) using Medline, Embase, and the Cochrane Library was performed for publications up to September 2022. New recommendations were developed and categorized according to the EULAR grading levels, as done for previous CanVasc recommendations. A modified Delphi procedure and videoconferences were used to reach ≥80% consensus on the inclusion, wording and grading of each recommendation. RESULTS: Three new recommendations were developed. They focus on avacopan therapy indication and duration, as well as timely glucocorticoid tapering. CONCLUSION: These 2022 addended recommendations provide rheumatologists, nephrologists and other specialists caring for patients with AAV with guidance for the use of avacopan, based on current evidence and consensus from Canadian experts.

Validation of the parent global assessment as a health-related quality of life measure in juvenile idiopathic arthritis: results from ReACCh-Out.

OBJECTIVES: To (i) validate the JIA parent global assessment (parent global) as a health-related quality of life (HRQoL) instrument; (ii) evaluate measurement properties of accepted HRQoL measures relative to those of the parent global; and (iii) assess causal pathways determining parent global scores. METHODS: Data from the Research in Arthritis in Canadian Children emphasizing outcomes (ReACCh-Out) cohort were used. Measurement properties were assessed in 344 patients at enrolment and 6 months later. Causal pathways were tested by structural equation modelling to understand root causes and mediators leading to parent global scores. RESULTS: Construct validity was supported by Spearman correlations of 0.53-0.70 for the parent global with the Juvenile Arthritis Quality of Life Questionnaire, Quality of My Life health scale (HRQoML), Pediatric Quality of Life Inventory (PedsQL)-Parent, and Child Health Questionnaire (CHQ)-Physical. Exceptions were PedsQL-Child (0.44) and CHQ-Psychosocial (0.31). Correlations were lower (0.14-0.49) with disease activity measures (physician global assessment of disease activity, active joint count, ESR). Responsiveness of the parent global to improvement according to parent ratings (0.51) was acceptable and within the range (0.32-0.71) of that of other measures. Reliability estimates and measurement errors for all measures were unsatisfactory, likely due to the prolonged time between assessments. Causal pathways for the parent global matched those previously reported for HRQoML. CONCLUSIONS: Our results offer support for the parent global as a valid measure of HRQoL for JIA. If confirmed, existing studies using the parent global may be re-interpreted, enhancing our knowledge of HRQoL in children with JIA.

Canadian Rheumatology Association Recommendations for the Screening, Monitoring, and Treatment of Juvenile Idiopathic Arthritis-Associated Uveitis.

OBJECTIVE: To develop Canadian recommendations for the screening, monitoring, and treatment of uveitis associated with juvenile idiopathic arthritis (JIA). METHODS: Recommendations were developed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE)-ADOLOPMENT approach. A working group of 14 pediatric rheumatologists, 6 ophthalmologists, 2 methodologists, and 3 caregiver/patient representatives reviewed recent American College of Rheumatology (ACR)/Arthritis Foundation (AF) recommendations and worked in pairs to develop evidence-to-decision (EtD) tables. A survey to assess agreement and recommendations requiring group discussion was completed. EtD tables were presented, discussed, and voted upon at a virtual meeting, to produce the final recommendations. A health equity framework was applied to all aspects of the adolopment process including the EtD tables, survey responses, and virtual meeting discussion. RESULTS: The survey identified that 7 of the 19 recommendations required rigorous discussion. Seventy-five percent of working group members attended the virtual meeting to discuss controversial topics as they pertained to the Canadian environment, including timing to first eye exam, frequency of screening, escalation criteria for systemic and biologic therapy, and the role of nonbiologic therapies. Equity issues related to access to care and advanced therapeutics across Canadian provinces and territories were highlighted. Following the virtual meeting, 5 recommendations were adapted, 2 recommendations were removed, and 1 was developed de novo. CONCLUSION: Recommendations for JIA-associated uveitis were adapted to the Canadian context by a working group of pediatric rheumatologists, ophthalmologists with expertise in the management of uveitis, and parent/patient input, taking into consideration cost, equity, and access.

Modified Juvenile Spondyloarthritis Disease Activity Index in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry.

OBJECTIVE: To validate the Juvenile Spondyloarthritis Disease Activity Index (JSpADA), and modified versions thereof, in a North American cohort of patients with enthesitis-related arthritis (ERA). METHODS: We utilized the Childhood Arthritis and Rheumatology Research Alliance Registry database ERA cohort to validate the JSpADA and its modifications (JSpADA6-no Schober, no C-reactive protein [CRP]/erythrocyte sedimentation rate [ESR]; JSpADA7-no Schober; and JSpADA7-no CRP/ESR) using the Outcome Measures in Rheumatology principles of face validity, discriminative validity, and responsiveness to change. RESULTS: There were 51 subjects (64 visits) with complete JSpADA data with a mean age of 13.7 years and disease duration of 30.9 months. Subjects were predominantly White (84.3%), and 56.9% were male and 50% were HLA-B27 positive. The JSpADA showed high correlation with the clinical 10-joint Juvenile Arthritis Disease Activity Score (cJADAS10; r = 0.81), moderate-to-high correlation with physician global assessment (PGA; r = 0.69), and low-to-fair correlation with Childhood Health Assessment Questionnaire (CHAQ; r = 0.22). The modifications of the JSpADA (JSpADA7-no Schober; JSpADA7-no CRP/ESR; and JSpADA6-no Schober, no CRP/ESR) performed similarly with high correlation with cJADAS10 (r = 0.81, 0.79, and 0.80, respectively), moderate-to-high correlation with PGA (r = 0.65, 0.67, 0.64, respectively), and low-to-fair correlation with CHAQ (r = 0.35, 0.34, 0.39, respectively). All modified versions of JSpADA had good responsiveness to change. All versions of JSpADA had excellent discriminative validity. CONCLUSION: We propose the term modified JSpADA for the modification of JSpADA with 6 elements (JSpADA6-no Schober, no CRP/ESR). This shorter disease activity index may improve implementation of JSpADA in both clinical practice and research trials.

Comparing Canadian paediatric rheumatology practice to the 2019 ACR Juvenile Idiopathic Arthritis guidelines: results from the CAPRI Registry.

OBJECTIVE: To identify differences between baseline Canadian JIA practices and the 2019 ACR guidelines for JIA. METHODS: Canadian paediatric rheumatologists were surveyed for their opinions on reasonable a priori target adherence rates for JIA guideline recommendations. Prospectively collected data for 266 newly diagnosed children from 2017 to 2019 were analysed to calculate observed adherence rates. Kaplan-Meier survival curves were used to estimate the cumulative incidence of starting synthetic or biologic DMARDs (sDMARD or bDMARD, respectively) for different patient groups. RESULTS: A total of 25/61 (41%) eligible physicians answered the survey. Most survey respondents (64%) felt that adherence targets should vary depending on the strength of the recommendation and quality of evidence, from a mean of 84% for strong recommendations with high-quality evidence to 29% for conditional recommendations with very low-quality evidence. Data showed 13/19 (68%) recommendations would have met proposed targets and 10/19 (53%) had ≥80% observed adherence. Exceptions were the use of subcutaneous vs oral MTX (53%) and infrequent treatment escalation from NSAIDs to bDMARDs in patients with sacroiliitis (31%) or enthesitis (0%). By 12 weeks, 95% of patients with polyarthritis received sDMARDs, 38% of patients with systemic JIA received bDMARDs and 22% of patients with sacroiliitis received bDMARDs. CONCLUSION: Canadian paediatric rheumatology practices were in line with many 2019 JIA guideline recommendations before their publication, except for frequent use of oral MTX and infrequent direct escalation from NSAIDs to bDMARDs in sacroiliitis and enthesitis.

Reproducibility of the Six-Minute Walk Test in Children and Youth With Juvenile Idiopathic Arthritis.

OBJECTIVE: While the 6-minute walk test is increasingly being used in research to evaluate submaximal exercise capacity of children with juvenile idiopathic arthritis (JIA), psychometric properties with this population have not been well evaluated. We undertook this study to evaluate reproducibility (agreement and test-retest reliability) and to determine standard error of measurement (SEM) and smallest detectable difference (SDD) in children and youth with JIA. METHODS: Participants (n = 22, mean ± SD age 13.1 ± 1.1 years, 63.6% female) completed a 6-minute walk test as part of their routine clinical assessment, and then repeated the 6-minute walk test at mean ± SD 8 ± 1.2 days later, in the same clinical setting with the same rater. RESULTS: The intraclass correlation coefficient (95% confidence interval) was 0.86 (0.66-0.94); the SEM and SDD were 23.5 and 65.1 meters, respectively. CONCLUSION: These results provide evidence of good-excellent reproducibility of the 6-minute walk test with children and youth with JIA and support the use of the 6-minute walk test as a measure of submaximal exercise capacity in clinical practice and research.

Parent-Reported Medication Side Effects and Their Impact on Health-Related Quality of Life in Children With Juvenile Idiopathic Arthritis.

OBJECTIVE: To describe the frequency and severity of parent-reported medication side effects (SEs) in children with juvenile idiopathic arthritis (JIA) relative to physician-reported actionable adverse events (AEs), and to assess their impact on health-related quality of life (HRQoL). METHODS: Newly diagnosed JIA patients recruited between 2017 and 2019 to the Canadian Alliance of Pediatric Rheumatology Investigators (CAPRI) Registry were included. Parents reported presence and severity (0 = no problem, 10 = very severe) of medication SEs at every clinic visit. Physicians were asked to report any actionable AE. HRQoL was assessed using the Quality of My Life (QoML) questionnaire (0 = the worst, 10 = the best) and parent's global assessment (0 = very well, 10 = very poor). Analyses included proportion of visits with SEs or actionable AEs, cumulative incidence by Kaplan-Meier methods, and HRQoL impact measured with longitudinal mixed-effects models. RESULTS: SEs were reported at 371 of 884 (42%) visits (95% confidence interval [95% CI] 39, 45%) in 249 patients, with a median of 2 SEs per visit (interquartile range [IQR] 1-3), and median severity of 3 (IQR 1.5-5). Most SEs were gastrointestinal (32.5% of visits) or behavioral/psychiatric (22.4%). SE frequency was lowest with nonsteroidal antiinflammatory drugs alone (34.7%) and highest with prednisone and methotrexate combinations (66%). SE cumulative incidence was 67% (95% CI 59, 75) within 1 year of diagnosis, and 36% (95% CI 28, 44) for actionable AEs. Parent global and QoML scores were worse with SEs present; the impact persisted after adjusting for pain and number of active joints. CONCLUSION: Parents report that two-thirds of children with JIA experience SEs impacting their HRQoL within 1 year of diagnosis. SE mitigation strategies are needed in managing JIA.

Reference Values for the Six Minute Walk Test in Children with Juvenile Idiopathic Arthritis.

AIMS: To (1) describe six-minute walk test (6MWT) reference values for children with Juvenile Idiopathic Arthritis (JIA) and (2) explore predictors of 6MWT distance. A secondary objective was to determine how 6MWT distances of children with JIA compare to those of children without JIA reported in the literature. METHODS: Demographic, clinical, height, weight and 6MWT data were extracted from clinical records of 120 children with JIA (70.8% female, mean age=12.4 ± 3.2 years) who attended a follow-up rheumatology clinic. A total of 272 6MWTs were included in the analyses. Linear mixed effects modeling was used to determine the relationship between predictive variables and 6MWT distance. 6MWT distances were compared to predicted values using published equations for estimating 6MWT distances in children without JIA. RESULTS: Height, weight, and age were predictive of 6MWT distance (R2 = 0.62). Mean 6MWT distances for children with JIA were lower than those reported for children without JIA (p < 0.001). Mean 6MWT distance was 84% and 78% of predicted values for children without JIA. CONCLUSION: The reference values and associated predictive model have application for assessing exercise capacity in children with JIA.

Impact of the COVID-19 pandemic on juvenile idiopathic arthritis presentation and research recruitment: results from the CAPRI registry.

OBJECTIVE: The COVID-19 pandemic has disrupted healthcare delivery and clinical research worldwide, with data from areas most affected demonstrating an impact on rheumatology care. This study aimed to characterize the impact of the pandemic on the initial presentation of JIA and JIA-related research in Canada. METHODS: Data collected from the Canadian Alliance of Pediatric Rheumatology Investigators JIA Registry from the year pre-pandemic (11 March 2019 to 10 March 2020) was compared with data collected during the first year of the pandemic (11 March 2020 to 10 March 2021). Outcomes included time from symptom onset to first assessment, disease severity at presentation and registry recruitment. Proportions and medians were used to describe categorical and continuous variables, respectively. RESULTS: The median time from symptom onset to first assessment was 138 (IQR 64-365) days pre-pandemic vs 146 (IQR 83-359) days during the pandemic. The JIA category frequencies remained overall stable (44% oligoarticular JIA pre-pandemic, 46.8% pandemic), except for systemic JIA (12 cases pre-pandemic, 1 pandemic). Clinical features, disease activity (cJADAS10), disability (CHAQ) and quality of life (JAQQ) scores were similar between the two cohorts. Pre-pandemic, 225 patients were enrolled, compared with 111 in the pandemic year, with the greatest decrease from March to June 2020. CONCLUSIONS: We did not observe the anticipated delay in time to presentation or increased severity at presentation, suggesting that, within Canada, care adapted well to provide support to new patient consults without negative impacts. The COVID-19 pandemic was associated with an initial 50% decrease in registry enrolment but has since improved.

Changes over time in inflammatory and structural lesions at the sacroiliac joint in children with spondyloarthritis exposed and unexposed to tumor necrosis factor inhibitor.

BACKGROUND: The objective of this work was to describe magnetic resonance imaging (MRI) changes over time in inflammatory and structural lesions at the sacroiliac joint (SIJ) in children with spondyloarthritis (SpA) exposed and unexposed to tumor necrosis factor inhibitor (TNFi). METHODS: This was a retrospective, multicenter study of SpA patients with suspected or confirmed sacroiliitis who underwent at ≥2 pelvic MRI scans. Images were reviewed independently by 3 radiologists and scored for inflammatory and structural changes using the Spondyloarthritis Research Consortium of Canada (SPARCC) SIJ inflammation score (SIS) and structural score (SSS). Longitudinal, quantitative changes in patient MRI scans were measured using descriptive statistics and stratified by TNFi exposure. We used an average treatment effects (ATE) regression model to explore the average effect of TNFi exposure over time on inflammatory and structural lesions, adjusting for baseline lesion scores. RESULTS: Forty-six subjects were evaluated using the SIS (n = 45) and SSS (n = 18). Median age at baseline imaging was 13.6 years, 63% were male and 71% were white. Twenty-three subjects (50%) were TNFi exposed between MRI studies. The median change in SIS in TNFi exposed and unexposed subjects with a baseline SIS ≥0 was - 20.7 and - 14.3, respectively (p = 0.09). Eleven (85%) TNFi exposed and 8 (89%) unexposed subjects with a baseline SIS ≥0 met the SIS minimal clinically important difference (MCID; ≥2.5). Using the ATE model adjusted for baseline SIS, the average effect of TNFi on SIS in patients with a baseline SIS ≥2 was - 14.5 (p < 0.01). Unadjusted erosion change score was significantly worse in TNFi unexposed versus exposed subjects (p = 0.03) but in the ATE model the effect of TNFi was not significant. CONCLUSION: This study quantitatively describes how lesions in the SIJs on MRI change over time in patients exposed to TNFi versus unexposed. Follow-up imaging in TNFi exposed patients showed greater improvement than the unexposed group by most metrics, some of which reached statistical significance. Surprisingly, a majority of TNFi unexposed children with a baseline SIS≥2 met the SIS MCID. Additional studies assessing the short and long-term effects of TNFi on inflammatory and structural changes in juvenile SpA are needed.

Juvenile Idiopathic Arthritis Treatment Updates.

Juvenile idiopathic arthritis is a group of heterogeneous chronic inflammatory arthropathies occurring in childhood without a known cause. This article discusses the key clinical features of juvenile idiopathic arthritis and treatment updates for oligoarthritis, polyarthritis, enthesitis-related arthritis, psoriatic arthritis, and systemic arthritis. Paradigm changes in management include the earlier use of biologic agents and the introduction of biosimilars and targeted synthetic disease modifying agents like tofacitinib. This review summarizes recent developments while considering potential areas for improvement and study.

Consensus-driven conceptual development of a standardized whole body-MRI scoring system for assessment of disease activity in juvenile idiopathic arthritis: MRI in JIA OMERACT working group.

OBJECTIVES: Whole body-MRI is helpful in directing diagnostic and treatment approaches, and as a research outcome measure. We describe our initial consensus-driven phase towards developing a whole body-MRI scoring system for juvenile idiopathic arthritis. METHODS: An iterative approach using three rounds of anonymous Delphi surveys followed by a consensus meeting was used to draft the structure of the whole body-MRI scoring system, including the relevant anatomic joints and entheses for assessment, diagnostic item selection, definition and grading, and selection of appropriate MRI planes and sequences. The surveys were completed independently by an international expert group consisting of pediatric radiologists and rheumatologists. RESULTS: Twenty-two experts participated in at least one of three rounds of Delphi surveys and a concluding consensus meeting. A first iteration scoring system was developed which ultimately included the assessment of 100 peripheral, 23 chest, and 76 axial joints, and 64 entheses, with 2-4 diagnostic items graded in each of the items, using binary (presence/absence) and 2-3-level ordinal scores. Recommendations on anatomic MRI planes and sequences were specified as the minimally necessary imaging protocol for the scoring system. CONCLUSION: A novel whole body-MRI scoring system for juvenile idiopathic arthritis was developed by consensus among members of MRI in JIA OMERACT working group. Further iterative refinements, reliability testing, and responsiveness are warranted in upcoming studies.

Patterns of etanercept use in juvenile idiopathic arthritis in the Childhood Arthritis and Rheumatology Research Alliance Registry.

BACKGROUND: We aimed to characterize etanercept (ETN) use in juvenile idiopathic arthritis (JIA) patients enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry. METHODS: The CARRA Registry is a convenience cohort of patients with paediatric onset rheumatic diseases, including JIA. JIA patients treated with ETN for whom the month and year of ETN initiation were available were included. Patterns of ETN and methotrexate (MTX) use were categorized as follows: combination therapy (ETN and MTX started concurrently), step-up therapy (MTX started first and ETN added later), switchers (MTX started and then stopped when or before ETN started), MTX add-on (ETN started first and MTX added later), and ETN only (no MTX use). Data were described using parametric and non-parametric statistics as appropriate. RESULTS: Two thousand thirty-two of the five thousand six hundred forty-one patients with JIA met inclusion criteria (74% female, median age at diagnosis 6.0 years [interquartile range 2.0, 11.0]. Most patients (66.9%) were treated with a non-biologic disease modifying anti-rheumatic drug (DMARD), primarily MTX, prior to ETN. There was significant variability in patterns of MTX use prior to starting ETN. Step-up therapy was the most common approach. Only 34.0% of persistent oligoarticular JIA patients continued treatment with a non-biologic DMARD 3 months or more after ETN initiation. ETN persistence overall was 66.3, 49.4, and 37.3% at 24, 36 and 48 months respectively. ETN persistence among spondyloarthritis patients (enthesitis related arthritis and psoriatic JIA) varied by MTX initiation pattern, with higher ETN persistence rates in those who initiated combination therapy (68.9%) and switchers/ETN only (73.3%) patients compared to step-up (65.4%) and MTX add-on (51.1%) therapy. CONCLUSION: This study characterizes contemporary patterns of ETN use in the CARRA Registry. Treatment was largely in keeping with American College of Rheumatology guidelines.

Case Report: Novel SAVI-Causing Variants in STING1 Expand the Clinical Disease Spectrum and Suggest a Refined Model of STING Activation.

Gain-of-function mutations in STING1 cause the monogenic interferonopathy, SAVI, which presents with early-onset systemic inflammation, cold-induced vasculopathy and/or interstitial lung disease. We identified 5 patients (3 kindreds) with predominantly peripheral vascular disease who harbor 3 novel STING1 variants, p.H72N, p.F153V, and p.G158A. The latter two were predicted by a previous cryo-EM structure model to cause STING autoactivation. The p.H72N variant in exon 3, however, is the first SAVI-causing variant in the transmembrane linker region. Mutations of p.H72 into either charged residues or hydrophobic residues all led to dramatic loss of cGAMP response, while amino acid changes to residues with polar side chains were able to maintain the wild type status. Structural modeling of these novel mutations suggests a reconciled model of STING activation, which indicates that STING dimers can oligomerize in both open and closed states which would obliviate a high-energy 180° rotation of the ligand-binding head for STING activation, thus refining existing models of STING activation. Quantitative comparison showed that an overall lower autoactivating potential of the disease-causing mutations was associated with less severe lung disease, more severe peripheral vascular disease and the absence of a robust interferon signature in whole blood. Our findings are important in understanding genotype-phenotype correlation, designing targeted STING inhibitors and in dissecting differentially activated pathways downstream of different STING mutations.

Causal pathways to health-related quality of life in children with juvenile idiopathic arthritis: results from the ReACCh-Out cohort.

OBJECTIVE: Structural equation modelling was applied to data from the Research in Arthritis in Canadian Children emphasizing Outcomes (ReACCh-Out) cohort to help elucidate causal pathways to decreased health-related quality of life (HRQoL) in children with JIA. METHODS: Based on published literature and clinical plausibility, a priori models were constructed with explicit root causes (disease activity, treatment intensity) and mediators (pain, disease symptoms, functional impairments) leading to HRQoL [measured by the Quality of my Life (QoML) scale and the Juvenile Arthritis Quality of Life Questionnaire (JAQQ)] at five disease stages: (i) diagnosis, (ii) 3-9 months after diagnosis, (iii) flare, (iv) remission on medications, (v) remission off medications. Following structural equation modelling, a posteriori models were selected based on data fit and clinical plausibility. RESULTS: We included 561, 887, 137, 186 and 182 patients at each stage, respectively. In a posteriori models for active disease stages, paths from disease activity led through pain, functional impairments, and disease symptoms, directly or through restrictions in participation, to decreased QoML scores. Treatment intensity had detrimental effects through psychosocial domains; while treatment side effects had a lesser role. Pathways were similar for QoML and JAQQ, but JAQQ models provided greater specificity. Models for remission stages were not supported by the data. CONCLUSION: Our findings support disease activity and treatment intensity as being root causes of decreased HRQoL in children with JIA, with pain, functional impairments, and participation restrictions being mediators for disease activity; they support psychosocial effects and side effects as being mediators for treatment intensity.

Juvenile Spondyloarthritis in the Childhood Arthritis and Rheumatology Research Alliance Registry: High Biologic Use, Low Prevalence of HLA-B27, and Equal Sex Representation in Sacroiliitis.

OBJECTIVE: To describe characteristics of children with enthesitis-related arthritis (ERA) and juvenile psoriatic arthritis (PsA) who were enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) registry. METHODS: All children with ERA and those with juvenile PsA were identified. Demographic characteristics, clinical characteristics, and treatments were described. The children with sacroiliitis and those without sacroiliitis were compared. In the children with sacroiliitis, the first visit with clinically active sacroiliitis (which came first in 72% of cases) was compared to the first visit without clinically active sacroiliitis. RESULTS: A total of 902 children with ERA or juvenile PsA were identified. Children with ERA were older at diagnosis (ages 10.8 years versus 8.2 years; P < 0.01) and were more likely to be male (56% versus 38%; P < 0.01). Polyarticular involvement was reported in 57% of children with ERA and in 72% of those with juvenile PsA. Of the children tested, HLA-B27 was positive in 38% of those in the ERA group and in 12% of those in the juvenile PsA group. At least 1 biologic was taken by 72% of those with ERA and 64% of those with juvenile PsA. Sacroiliitis (diagnosed clinically and/or by imaging) was reported in 28% of the children (40% of those with ERA and 12% of those with juvenile PsA). Of these, 54% of the children were female, 36% were HLA-B27 positive, and 81% took at least 1 biologic. In children with sacroiliitis, scores according to the physician global assessment of disease activity, parent/patient global assessment of well-being, and clinical Juvenile Arthritis Disease Activity Score 10 were all significantly worse at the first visit with clinically active sacroiliitis versus the first visit without active sacroiliitis. CONCLUSION: In this registry, there are more than 900 children with ERA or juvenile PsA. There was high biologic use in this population, especially in those with sacroiliitis. Further, there was equal sex representation in those children with sacroiliitis.