Prospective validation of the Juvenile Spondyloarthritis Disease Activity Index in children with enthesitis-related arthritis

Pediatric Society of the African League Against Rheumatism juvenile idiopathic arthritis recommendations for enthesitis-related arthritis and juvenile psoriatic arthritis

The objective of this study is to develop evidence-based recommendations for the diagnosis and management of enthesitis-related arthritis (ERA) and juvenile psoriatic arthritis (JPsA) in the African context. The recommendations for ERA and JPsA were combined into a single document. The steering committee and task force identified 15 key questions and formulated 35 research questions. A comprehensive literature review, utilizing Medline and a manual search for African local data, was conducted to gather evidence. Following this synthesis, the task force developed draft recommendations and engaged in a Delphi process with an expert panel, including 17 African and three international experts, to reach a consensus and ensure alignment with global standards. The final recommendations were assigned a level of evidence and subsequently approved by the task force members, the expert panel, and the PAFLAR Board. Fifteen recommendations on the diagnosis and management of ERA and JPsA were developed, covering the role of the pediatric rheumatologist in multiple aspects of disease management, including diagnosis, monitoring of disease and extra-articular manifestations, determining treatment strategies, and guiding interventions. The level of evidence supporting these recommendations was variable, leading to the identification of a research agenda to address African particularities and answer pending questions. The final recommendations achieved a high level of agreement, with consensus ranging from 90 to 100%. These recommendations represent an important achievement for pediatric rheumatology in Africa, being the first of their kind, tailored specifically to the region. Developed through a rigorous methodology and collaboration between international and African experts, they aim to standardize care and address the unique challenges faced in African setting.

Prevalence of HLA-B27, clinical characteristics and treatment outcomes in children with enthesitis-related arthritis

BACKGROUND

Enthesitis-related arthritis (ERA) is a subtype of juvenile idiopathic arthritis with high disease burden. The objectives of this study were to explore the prevalence of HLA-B27, clinical characteristics, and treatment outcomes in children with ERA and compare the differences between HLA-B27 positive and negative patients.

METHODS

A retrospective cohort study at a pediatric rheumatology clinic in a tertiary referral hospital in Bangkok, Thailand, including ERA patients with at least 6 months of follow-up (July 2011-April 2022) was performed. Data were collected from medical records from diagnosis to recent follow-up, assessing disease activity and treatment outcomes, with an analysis comparing HLA-B27 positive and negative patients. Descriptive statistics were used for data analysis.

RESULTS

There were 59 ERA patients with mean age ± SD at diagnosis 11.2 ± 2.5 years, 53 males (89.8%), and positive HLA-B27 in 38 patients (64.4%). The HLA-B27 positive group had significantly higher levels of inflammatory markers at initial diagnosis (p = 0.001), lower baseline hemoglobin (p = 0.001) and hematocrit (p = 0.002), higher disease activity assessed by the Juvenile Spondyloarthritis Disease Activity score at 6 and 12 months of follow-up (p = 0.028 and 0.040, respectively), increased utilization of bridging systemic corticosteroids (60.5% vs. 14.3%, p = 0.001) and anti-TNF (39.5% vs. 9.5%, p = 0.018), and longer duration of methotrexate (median[IQR] 1.7[1.1-3.1] vs. 1.3[0.6-1.9] years, p = 0.040). The HLA-B27 negative group had more prevalent hip arthritis than the positive group at initial diagnosis (66.7% vs. 28.9%, p = 0.005) and during the course of the disease (71.4% vs. 36.8%, p = 0.011).

CONCLUSION

Most of the ERA patients tested positive for HLA-B27. Throughout the follow-up period, these patients demonstrated greater disease activity, greater use of corticosteroids and anti-TNF, and longer duration of methotrexate to control the disease.

Presentation of enthesitis-related arthritis and juvenile-onset spondyloarthritis: a cross-sectional study in a pediatric and adult clinic

BACKGROUND

Juvenile idiopathic arthritis (JIA) comprises a whole spectrum of chronic arthritis starting before 16 years of age. The study aims to explore the clinical and demographic descriptors, treatment, and disease progression of enthesitis-related arthritis (ERA) in comparison with juvenile-onset spondyloarthritis (SpA).

METHODS

Cross-sectional analysis of consecutive patients in two dedicated clinics, with a single visit and retrospective case-notes review. Arthritis, enthesitis and sacroiliitis were evaluated by scoring disease activity and damage. Continuous variables were reported by median, interquartile range; categorical variables were reported by the frequency comparison of the two groups.

RESULTS

Thirty-three cases were included, being 23 (69.7%) with ERA. The median age at diagnosis was 12.5 y (SpA) vs. 9 y (ERA) (p < 0.01); the time from symptom onset to diagnosis was 5.5 y (SpA) vs. 1.5 y (ERA) (p < 0.03). In both groups, the predominant presentation was a single joint or < 5 lower limb joints and asymmetric involvement, with a high frequency of enthesitis. There was a higher frequency of mid-tarsal and ankle synovitis in the ERA group and hip involvement in those with SpA. The comparison of the frequency of spine symptoms at presentation, 30% SpA vs. 21.7% ERA (p = 0.7), was not significant, and radiographic progression to spinal involvement occurred in 43.5% of ERA patients. The median time for spinal progression and age at onset was 2.2 and 12 y for ERA, and 4 and 16.5 y for SpA, respectively. Activity and damage scores were not significantly different between the groups. Treatment comparison resulted in 91.3% of ERA and 100% SpA being treated, predominantly with NSAIDs in both groups, followed by DMARDs and biologics, with a higher frequency of biologics in SpA.

CONCLUSION

The main differences were the late diagnoses of SpA, and the hip and spine involvement, with higher frequency of biologic treatment in juvenile-onset SpA compared to ERA.

Advances in the Diagnosis and Treatment of Enthesitis-Related Arthritis

Enthesitis-related arthritis (ERA) represents 5-30% of all cases of juvenile idiopathic arthritis (JIA) and belongs to the spectrum of the disorders included in the group of juvenile spondyloarthritis. In the last decade, there have been considerable advances in the classification, diagnosis, monitoring, and treatment of ERA. New provisional criteria for ERA have been recently proposed by the Paediatric Rheumatology INternational Trials Organisation, as part of a wider revision of the International League of Associations for Rheumatology criteria for JIA. The increased use of magnetic resonance imaging has shown that a high proportion of patients with ERA present a subclinical axial disease. Diverse instruments can be used to assess the disease activity of ERA. The therapeutic recommendations for ERA are comparable to those applied to other non-systemic JIA categories, unless axial disease and/or enthesitis are present. In such cases, the early use of a TNF-alpha inhibitor is recommended. Novel treatment agents are promising, including IL-17/IL-23 or JAK/STAT pathways blockers.

The Juvenile Spondyloarthritis Disease Activity Index Is a Useful Tool in Enthesitis-Related Arthritis: Real-Life Data

OBJECTIVE

To compare enthesitis-related arthritis (ERA) patients with active and inactive disease at 6 months and define baseline predictors for disease inactivity. In addition, to evaluate the demographic, clinical, and laboratory characteristics of ERA patients and to identify the real-life impact of the Juvenile Spondyloarthritis Disease Activity Index (JSpADA) in predicting active disease in ERA.

METHODS

This medical record review study was conducted with 56 patients who were diagnosed with ERA at our clinic between June 2009 and June 2022. Demographic and clinical characteristics, laboratory parameters, treatment, and JSpADA were recorded.

RESULTS

The patients were divided into 2 groups as active (n = 34) and inactive (n = 22) according to their disease activity at month six. Sex, age at diagnosis, number and type of affected joints, and presence of sacroiliitis were similar in both groups. There was no difference in baseline erythrocyte sedimentation rate, but there was a significant difference in erythrocyte sedimentation rate at the third month ( p = 0.52 and p = 0.018, respectively). The median JSpADA values at disease onset were 3.5 (interquartile range [IQR], 3.0-4.5) and 3.3 (IQR, 2.5-4.0) in the active and inactive groups, respectively ( p = 0.27). At the third month, the median JSpADA values were 1.5 (IQR, 0.5-2.1) in the active group and 0.5 (IQR, 0.5-1.5) in the inactive group ( p = 0.037). The cutoff value for JSpADA at the third month for active disease persisting at the month six was determined as 1 point (area under the curve, 0.662 ± 0.06; p = 0.042; 95% confidence interval, 0.51-0.80) by receiver operating characteristic curve analysis.

CONCLUSION

In ERA patients, a persistently high JSpADA value at follow-up is a predictive factor for active disease at the sixth month.

Childhood-Onset Sacroiliitis: Causes and Correlation Between Clinical Findings and Magnetic Resonance Imaging

OBJECTIVE

The aims of this study were to describe disease associations of magnetic resonance imaging (MRI)-confirmed and clinically symptomatic sacroiliitis in pediatric patients with rheumatic diseases and to examine the relationship between patient characteristics and MRI findings of the sacroiliac joint (SIJ).

METHODS

Demographic and clinical data were extracted from the electronic medical records of the patients with sacroiliitis followed in the last 5 years. Active inflammatory and structural damage lesions of the SIJ-MRI were examined by the modified Spondyloarthritis Research Consortium of Canada scoring system, and correlation analysis of these results with clinical characteristics was evaluated.

RESULTS

A total of 46 symptomatic patients were found to have MRI-proven sacroiliitis of 3 different etiologies: juvenile idiopathic arthritis (JIA) (n = 17), familial Mediterranean fever (FMF) (n = 14), and chronic nonbacterial osteomyelitis (CNO) (n = 8). Seven patients, FMF and JIA (n = 6) and FMF and CNO (n = 1), had a co-diagnosis that might cause sacroiliitis. Although inflammation scores and structural damage lesions did not statistically differ between the groups, capsulitis and enthesitis on the MRI were more frequently detected in the CNO group. There was a negative correlation between symptom onset and inflammation scores of bone marrow edema. Disease composite scores and acute phase reactants were correlated with MRI inflammation scores.

CONCLUSIONS

We demonstrated that JIA, FMF, and CNO were the major rheumatic causes of sacroiliitis in children originating from the Mediterranean region. Quantitative MRI scoring tools can be used to assess the inflammation and damage of the SIJ in rheumatic diseases, show discrepancies between them, and have an important correlation with various clinical and laboratory features.

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.

Recent updates in enthesitis-related arthritis

Enthesitis-related arthritis (ERA) is a category of juvenile idiopathic arthritis which belongs to the spectrum of diseases that are included in juvenile spondyloarthropathy. In recent years, there have been significant advances in understanding pathogenesis, tools to assess disease activity, early recognition of the axial disease, and targeted therapy using IL-17 inhibitors and small molecule inhibitors. The current narrative review highlights these new advances. Among many hypotheses linking HLA B27 to ERA, one of them is the effect of HLA B27 on gut dysbiosis. However, recent data suggest that gut dysbiosis is probably not determined by HLA B27. Though children present with arthritis and enthesitis, axial disease is present in 50-60% on MRI. Using data-driven approach, discriminative MRI finding for active and chronic diseases has been defined for children. This will help in the early recognition of disease. An abridged version of juvenile spondyloarthropathy disease activity (JSpADA) score without the need for acute phase reactants and Schober test performed as well as the original score may increase its acceptance in routine practice. Secukinumab (anti-IL-17 antibody) has shown a more than 75% response rate in children with ERA and may be a good alternative to anti-TNF therapy. Initial data with tofacitinib also look promising. All these will translate into better outcomes for children with ERA.

Development and Validation of a Juvenile Spondyloarthritis Disease Flare Measure: Ascertaining Flare in Patients With Inactive Disease

OBJECTIVE

Our objective was to develop and validate a composite disease flare definition for juvenile spondyloarthritis (SpA) that would closely approximate the clinical decision made to reinitiate or not reinitiate systemic therapy after therapy de-escalation.

METHODS

Retrospective chart reviews of children with SpA who underwent systemic therapy de-escalation of biologic or conventional disease-modifying antirheumatic drugs were used to develop and validate the flare outcome. Data on independent cohorts for development (1 center) and validation (4 centers) were collected from large tertiary health care systems. Core measure thresholds and candidate disease flare outcomes were assessed using sensitivity, specificity, positive predictive values (PPVs) and negative predictive values (NPVs), and the receiver operating characteristic (ROC) area under the curve (AUC), with physician assessment of active disease plus re-initiation of standard dose of systemic therapy as the reference standard.

RESULTS

Of the candidate definitions, clinically meaningful worsening in ≥3 of the following 5 core measures performed best: caregiver/patient assessment of well-being; physician assessment of disease activity; caregiver/patient assessment of pain, physical function, and active joint count. The ROC AUC was 0.91, PPV 87.5%, NPV 98.1%, sensitivity 82.4%, and specificity 98.7%. Cronbach's α was 0.81, signifying internal consistency, and factor analysis demonstrated that the outcome measured 1 construct. The Juvenile SpA Flare measure had face validity according to 21 surveyed pediatric rheumatologists. Juvenile SpA Flare had an ROC AUC of 0.85, a PPV of 92.3%, and an NPV of 96.8% in the validation cohort.

CONCLUSION

There is initial support for the validity of the Juvenile SpA Flare measure as a tool to identify disease flare in juvenile SpA patients de-escalating therapy, and the measure is potentially applicable in clinical practice, observational studies, and therapeutic trials.

Macrophage migration inhibitory factor (MIF) and IgA anti CD74 antibodies in Indian patients with enthesitis-related arthritis category of Juvenile idiopathic arthritis

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine and has been implicated in pathogenesis of ankylosing spondylitis (AS). CD 74 is the receptor for MIF and IgA antiCD74 autoantibodies have been described from different parts of the world in patients with AS. As enthesitis-related arthritis (ERA) is a form of juvenile spondyloarthropathy, we studied the serum and synovial fluid levels of MIF in ERA and looked for the IgA antiCD74 antibodies in patients with ERA in our population. Patients with JIA (ILAR classification) were studied. Serum MIF levels were measured by ELISA in 101 patients of ERA (synovial fluid also where available) and compared to 28 patients of other categories of JIA, 25 patients each of ankylosing spondylitis and rheumatoid arthritis, and 38 healthy controls. In addition, association of MIF with disease activity was assessed. Ig A antiCD74 antibodies were measured in sera of ERA, AS and healthy controls. Median serum MIF levels were higher in ERA [2.50 (1.20-4.85) ng/ml] than in healthy controls [0.28 (0.16-0.48); p < 0.0001] and patients with RA [1.13 (0.44-2.45); p < 0.01] MIF levels in ERA were comparable to other categories of JIA [2.63 (1.70-4.05)] and patients with AS [3.62 (0.52-6.51)]. Synovial fluid MIF levels were higher than serum levels (p < 0.01). Serum MIF level had an association with the JSpADA score (r = 0.29, p < 0.01). Serum MIF levels had no association with presence of inflammatory markers, enthesitis, inflammatory back pain or sacroiliitis. IgA AntiCD74 antibody was positive only in 3/88 (3.41%) of ERA patients and was not detected in any patients of AS or healthy controls. Patients with ERA have high MIF levels that show modest correlation with disease activity. Higher synovial fluid MIF levels suggest that it may play a role in synovitis seen in ERA. IgA antiCD74 antibodies are rarely seen in ERA.

A randomized, double-blind, placebo-controlled 12-week trial of infliximab in patients with juvenile-onset spondyloarthritis

Objective

To assess the efficacy and safety of infliximab versus placebo in the treatment of patients with juvenile-onset spondyloarthritis (JoSpA).

Methods

Phase III, randomized, double-blind, placebo-controlled trial of 12 weeks that included patients ≤ 18 years old with JoSpA not responding to nonsteroidal anti-inflammatory drugs, sulfasalazine, or methotrexate. Patients were randomly assigned 1:1 to the infusion of infliximab 5mg/kg or placebo; completers entered then an open-label extension (OLE) period of 42 weeks. The primary endpoint was the number of active joints. Secondary outcomes included the assessment of disease activity, tender entheses, spinal mobility, serum C-reactive protein (CRP), the Bath Ankylosing Spondylitis Disease Activity and Functional Index, and the Childhood Health Assessment Questionnaire (CHAQ).

Results

We randomized 12 patients to infliximab and 14 to placebo. No significant differences were found between groups at baseline. At week 12, the mean number of active joints was 1.4 (SD 2.4) in the infliximab group and 4.1 (SD 3.0) in the placebo group (p = 0.0002). A repeated-measures mixed model analysis that included all endpoints in the study demonstrated sustained favourable outcomes of infliximab for active joints, tender joints, swollen joints, and tender enthesis counts, as well as for CHAQ and CRP (p < 0.01). Adverse events were more frequent in the infliximab group, including infections and infusion reactions, but none of them was serious.

Conclusion

Infliximab is efficacious for patients with JoSpA with an inadequate response to conventional treatment. No serious adverse events with the use of infliximab were observed.

Enthesitis-related arthritis: monitoring and specific tools

OBJECTIVES

In this article, the authors aimed to review the different tools used in the monitoring of enthesitis-related arthritis.

SOURCES

The authors performed a literature review on PubMed, Google Scholar, and Scopus databases. The dataset included the original research and the reviews including patients with enthesitis-related arthritis or juvenile spondylarthritis up to October 2020.

SUMMARY OF FINDING

Enthesitis-related arthritis is a category of juvenile idiopathic arthritis. It is characterized by the presence of enthesitis, peripheral arthritis, as well as axial involvement. The only validated tool for disease activity measurement in juvenile idiopathic arthritis is the Disease Activity Score: It has proven its reliability and sensitivity. Nevertheless, due to an absence of validated evaluation tools, the extent of functional impairment, as well as the children and parents' perception of the disease, could not be objectively perceived. Despite the great progress in the field of imaging modalities, the role they play in the evaluation of disease activity is still controversial. This is partially due to the lack of validated scoring systems.

CONCLUSIONS

Further work is still required to standardize the monitoring strategy and validate the outcome measures in enthesitis-related arthritis.

Doppler and Spectral Ultrasound of Sacroiliac Joints in Pediatric Patients with Suspected Juvenile Spondyloarthritis

Background: Power Doppler ultrasound (PDUS) with spectral wave analysis (SWA) has been compared with magnetic resonance imaging (MRI) in documenting active sacroiliitis in early spondyloarthritis (SpA) but, to date, PDUS/SWA has not been yet applied to the study of sacroiliac joints (SIJs) in children. Methods: A group of 20 children (13 F/7 M, mean age 14.2 y) with suspected juvenile SpA (jSpA) underwent PDUS/SWA and, subsequently, MRI of the SIJs. SIJs PDUS scoring and resistance index (RI) of the SIJs flows were recorded. The accuracy of PDUS/SWA for the diagnosis of active sacroiliitis was evaluated, with MRI as the gold standard. Results: PDUS signals were detected in 19 patients and 30 SIJs. Bone marrow edema (BME) lesions on MRI were detected in 12 patients (diagnosed as jSpA) and 22 SIJs. PDUS scoring on SIJs were higher in patients with a final diagnosis of jSpA (p = 0.003). On SWA, the mean RIs in patients with or without final diagnosis of active sacroiliitis were, respectively, 0.604 and 0.767 (p = 0.005) at joint level. A RI < 0.55 and PDUS > 1 showed the higher specificity for sacroiliitis (AUROC curve 0.854 for PDUS and 0.920 for RI). SIJs PDUS/SWA showed an overall concordance of 82.35%, with substantial agreement (k = 0.627) with MRI on the diagnosis of sacroiliitis. Conclusions: In children with sacroiliitis, PDUS demonstrates a rich vascularization into SIJs and low RIs (<0.55) have high specificity for this condition. SIJs PDUS/SWA could be useful as a screening method in children with suspected jSpA.

Recent Updates in Juvenile Spondyloarthritis

Spondyloarthritis represents a group of disorders characterized by enthesitis and axial skeletal involvement. Juvenile spondyloarthritis begins before age 16. Joint involvement is usually asymmetric. Bone marrow edema on noncontrast MRI of the sacroiliac joints can facilitate diagnosis. The most significant risk factor for axial disease is HLA-B27. Most patients have active disease into adulthood. Enthesitis and sacroiliitis correlate with greater pain intensity and poor quality-of-life measures. Tumor necrosis factor inhibitors are the mainstay of biologic therapy. Although other biologics such as IL-17 blockers have shown benefit in adult spondyloarthritis, none are approved by the US Food and Drug Administration.

Advances in Juvenile Spondyloarthritis

PURPOSE

To provide an overview of recent studies on pathogenesis, diagnosis, and management of juvenile spondyloarthritis (JSpA).

RECENT FINDINGS

Recent studies show differences in gut microbiome in patients with JSpA in comparison to healthy controls. There is increased recognition of the impact of the innate immune system on disease pathology. Normative reference on MRI of sacroiliac (SI) joints in children is now available. However, there is significant variability in interpretation of MRI of SI joints in children and a need for standardization. NSAIDs, physical therapy, and Tumor Necrosis Factor Inhibitors (TNFi) remain the mainstay of management for patients with JIA who have polyarthritis, sacroiliitis, and/or enthesitis as per recent ACR guidelines. Newer therapeutic options beyond TNFi are needed to manage patients who fail TNFi. This review highlights some of the recent advances in our knowledge of JSpA pathophysiology, diagnosis, and treatment. It also identifies areas in need of further research and standardization to improve our understanding and outcomes in JSpA.

Hip involvement in children with enthesitis related arthritis (ERA) is associated with poor outcomes in adulthood

Background

The data on long-term outcome in enthesitis-related arthritis (ERA), the commonest category of JIA in India, is scant. Thus, we studied outcomes of ERA in a resource-constrained setting.

Methods

Patients with ERA (ILAR classification) (≥ 5 years of disease and ≥ 18 years) were included. Data on clinical features, Bath indices (BASMI, BASDAI, BASFI), ASDAS, and health assessment questionnaire-disability index (HAQ-DI) was collected. X-ray pelvis including hips was obtained and compared with baseline X-ray for progression of sacroiliitis and hip arthritis. Fulfillment of adult criteria of spondyloarthropathy (SpA) were also assessed.

Results

Seventy-three 73 patients (72 males) of median age 20 (18–23) years and disease duration 8 (5.5–11) years were recruited. There was delay in diagnosis of 4 (1.75–6) years. Thirty-nine (53%) had BASDAI ≥ 4 and 63 (91%) had ASDAS-CRP > 1.3. Two-third (60%) had functional disability (HAQ-DI ≥ 0.5). Poor outcome (BASDAI ≥ 4, ASDAS > 2.1, BASFI > 0.9, or HAQ-DI ≥ 0.5) was seen in three-fourths (n = 56.76%) of patients and was associated with hip involvement, HLA-B27 positivity, and fulfillment of axial ASAS criteria. Sixty-seven (91%) patients fulfilled axial ASAS criteria, while 71 (97%) fulfilled peripheral ASAS criteria.

Overall, 81% had X-ray sacroiliitis and 37% had hip involvement. Nearly half (46.6%) and one-fourths (25%) of the patients had X-ray sacroiliitis and hip arthritis progression, respectively. Those with X-ray hip arthritis had longer delay in diagnosis (6 vs 3 years), higher Bath indices, ASDAS, and HAQ-DI. Hip arthritis correlated with radiological sacroiliitis (r = 0.301). Fulfillment of modified NY criteria was seen more often in patients with hip arthritis (95 vs 63%; p < 0.002).

Conclusion

Most ERA patients had active disease in adulthood. Hip involvement, axial involvement, and HLA-B27 positivity were predictors of poor outcome.

Key Points • Almost 90% of adults with ERA had active disease even after 8 years of disease. • Poor outcomes were seen in three-fourths of patients and hip involvement, presence of HLA B27, and axial involvement were the predictors of poor outcome.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10067-021-05807-3.

Similarities and Differences Between Juvenile and Adult Spondyloarthropathies

Spondyloarthritis (SpA) encompasses a broad spectrum of conditions occurring from childhood to middle age. Key features of SpA include axial and peripheral arthritis, enthesitis, extra-articular manifestations, and a strong association with HLA-B27. These features are common across the ages but there are important differences between juvenile and adult onset disease. Juvenile SpA predominantly affects the peripheral joints and the incidence of axial arthritis increases with age. Enthesitis is important in early disease. This review article highlights the similarities and differences between juvenile and adult SpA including classification, pathogenesis, clinical features, imaging, therapeutic strategies, and disease outcomes. In addition, the impact of the biological transition from childhood to adulthood is explored including the importance of musculoskeletal and immunological maturation. We discuss how the changes associated with adolescence may be important in explaining age-related differences in the clinical phenotype between juvenile and adult SpA and their implications for the treatment of juvenile SpA.

The Increased Levels of Fecal Calprotectin in Children With Active Enthesitis Related Arthritis and MRI Signs of Sacroiliitis: The Results of a Single Center Cross-Sectional Exploratory Study in Juvenile Idiopathic Arthritis Patients

Enthesitis related arthritis (ERA) is a specific subtype of juvenile idiopathic arthritis (JIA), often regarded as an undifferentiated form of juvenile spondyloarthritis (jSpA). While gut is increasingly recognized as origin and/or target of inflammation in adult onset spondyloarthritis (SpA), the incidence of gut involvement in ERA patients is largely unknown. The aim of this study was to measure the concentration of fecal calprotectin (fCAL), a surrogate marker of gut inflammation, in patients with different subtypes of JIA, as well as to correlate the results with various demographic, clinical, laboratory, imaging, and treatment characteristics. The cross-sectional exploratory study involving 71 patients with ERA, other forms of JIA and children complaining musculoskeletal symptoms was therefore conducted. Along with fCAL assessment, a detailed clinical and laboratory examination was performed, including the calculation of a composite disease activity scores. Moreover, MRI of the sacroiliac joints was performed in all ERA and other patients complaining of low back pain. The median concentration of fCAL was highest in ERA patients (33.2 mg/kg, p = 0.02), with a significant difference between those with inactive and active disease (20.0 vs. 57.4, p = 0.01), as well as those with and without MRI signs of sacroiliitis (22.6 vs. 54.3, p = 0.04). The fCAL did not differ depending on the NSAID use (23 vs. 20, p = 0.18), although weak correlation was observed with the treatment duration (r = 0.25, p = 0.03). In conclusion, our findings indicate that a parallel inflammation in musculoskeletal system and gut can occur not just in adults with SpA, but in children with ERA as well.

Biomarkers of Response to Biologic Therapy in Juvenile Idiopathic Arthritis

Background: Juvenile idiopathic arthritis (JIA) is the most common chronic inflammatory arthritis of childhood, characterized by various clinical phenotypes associated with variable prognosis. Significant progress has been achieved with the use of biologic treatments, which specifically block pro-inflammatory molecules involved in the disease pathogenesis. The most commonly used biologics in JIA are monoclonal antibodies and recombinant proteins targeting interleukins 1 (IL-1) and 6 (IL-6), and tumor necrosis factor α (TNF-α). Several biomarkers have been investigated in JIA. Aims: To assess the level of evidence available regarding the role of biomarkers in JIA related to guiding clinical and therapeutic decisions, providing disease prognostic information, facilitating disease activity monitoring and assessing biologic treatment response in JIA, as well as propose new strategies for biologic therapy-related biomarker use in JIA. Methods: We searched PubMed for relevant literature using predefined key words corresponding to several categories of biomarkers to assess their role in predicting and assessing biologic treatment response and clinical remission in JIA. Results: We reviewed serological, cellular, genetic, transcriptomic and imaging biomarkers, to identify candidates that are both well-established and widely used, as well as newly investigated in JIA on biologic therapy. We evaluated their role in management of JIA as well as identified the unmet needs for new biomarker discovery and better clinical applications. Conclusion: Although there are no ideal biomarkers in JIA, we identified serological biomarkers with potential clinical utility. We propose strategies of combining biomarkers of response to biologics in JIA, as well as routine implementation of clinically acceptable imaging biomarkers for improved disease assessment performance.

Do geography and ethnicity play a role in juvenile Spondyloarthritis? A multi-center binational retrospective study

BACKGROUND

Observations among Israeli pediatric rheumatologists reveal that pediatric Juvenile Spondyloarthritis (JSpA) may present differently compared to patients from the United States (US). This study is aimed to compare the demographic and clinical variables of Israeli and US JSpA patients upon presentation.

METHODS

We performed a retrospective, cross-sectional, multicenter comparison of JSpA patients among 3 large Israeli pediatric rheumatology centers and a large US pediatric rheumatology center. Patients with diagnosis of Juvenile Ankylosing Spondylitis (JAS) and/or Enthesitis-related Arthritis (ERA) were included. The demographic, clinical and radiologic features were compared.

RESULTS

Overall 87 patients were included (39 Israeli, 48 US patients). Upon presentation, inflammatory back pain, sacroiliac joint tenderness and abnormal modified Schober test, were significantly more prevalent among Israeli patients (59% vs. 35.4, 48.7% vs. 16.7, and 41.2% vs. 21.5%, respectively, all p < 0.05), whereas peripheral arthritis and enthesitis were significantly more prevalent among US patients (43.6% vs. 91.7 and 7.7% vs. 39.6% in Israeli patients vs. US patients, p < 0.05). In addition, 96.7% of the Israeli patients versus 29.7% of the US patients demonstrated sacroiliitis on MRI (p < 0.001, N = 67). Less than one-third of the Israeli patients (32%) were HLA-B27 positive vs. 66.7% of US patients (p = 0.007).

CONCLUSION

Israeli children with JSpA presented almost exclusively with axial disease compared to US patients who were more likely to present with peripheral symptoms. HLA B27 prevalence was significantly lower in the Israeli cohort compared to the US cohort. Further studies are needed to unravel the genetic and possibly environmental factors associated with these findings.

A prospective study of novel disease activity indices for ankylosing spondylitis

There is an ongoing quest for robust disease activity measures in Ankylosing spondylitis (AS). Thus, we prospectively validated two new disease activity indices, Simplified AS Disease Activity Score (SASDAS) and modified Juvenile Spondyloarthritis Disease Activity Score (JSpADA). Patients with AS were assessed for BASDAI, ASDAS and other outcome measures at baseline and 3 months. Comparisons were drawn between those with juvenile onset, early disease and peripheral involvement, with the rest. Fisher's r to Z transformation was used to compare correlations. Receiver-operating characteristic (ROC) curves were used to calculate cutoffs for inactive, low, high and very high disease activity. Of the 107 patients (mean age-29 years) of 6-years long disease, 38.3% had a juvenile onset. SASDAS and modified JSpADA exhibited excellent correlation with BASDAI and ASDAS (all p < 0.001) and were higher in active vs. inactive disease. Treatment responders had a greater fall in SASDAS and modified JSpADA as compared to non-responders. The novel scores were higher in those with peripheral disease. Only SASDAS could discriminate early from late disease. Based on the previously proposed cutoffs, optimal scores for inactive, moderate, high and very high disease activity were deduced. SASDAS-CRP showed better internal consistency than SASDAS-ESR and correlated better with ASDAS-CRP in late disease (Z = 3.04; p = 002) and those with adult onset disease (Z = 2.18; p = 0.03). SASDAS and Modified JSpADA perform as well as standard complex scores and have potential for simpler daily use. From our analyses, SASDAS with CRP performs better than SASDAS-ESR, pending further validation.

Capturing the enthesitis related arthritis contemporary profile of Caucasian patients in the era of biologics

To describe the profile of Enthesitis Related Arthritis' (ERA) patients, in the era of biologic DMARDs (bDMARDs). This retrospective cohort study included patients with ERA monitored on a 3-month schedule for at least 1 year. Their metric assessment included the disease status and damage by applying the contemporary tools clinical-Juvenile Arthritis Disease Activity Score (c-JADAS), Juvenile Spondyloarthritis Disease Activity Index (JSpADA), clinical remission (CR) on/off medication and Juvenile Arthritis Damage Index (JADI). 43 patients (males 26) were enrolled, with a mean disease onset of 10.75 years. Median lag time from diagnosis to bDMARDs was 8.5 months. Patients with sacroiliitis received earlier bDMARDs (hazard ratio, HR 3.26). 36/43 patients achieved CR on medication (median time 11 months), which was correlated with compliance (HR: 3.62). The percentage of CR in patients with or without sacroiliitis was 35% and 63% respectively (p = 0.02). Twenty patients (47%) experienced a flare following CR (75%). The median flare-free survival following CR on/off medication was 42 and 34 months, respectively. At the last evaluation, both median baseline cJADAS and JSpADA dropped to 0, 13/43 patients had a persistent disease activity, while 17/43 and 13/43 patients were in CR on/off medication, respectively. The median patient percentage of CR was 54% and no patient had a JADI > 0. Increased lag time to bDMARDs was associated with increased CR (Odds ratio: 1.48). Early administration of bDMARDs and compliance improved long-term outcome of ERA. Sacroiliitis was a negative prognostic factor with an increased need for bDMARDs and diminished rates of CR.