A decade of progress in juvenile idiopathic athritis treatments and outcomes in Canada: results from ReACCh-Out and the CAPRI registry

OBJECTIVE

To assess changes in juvenile idiopathic arthritis (JIA) treatments and outcomes in Canada, comparing a 2005-2010 and a 2017-2021 inception cohorts.

METHODS

Patients enrolled within three months of diagnosis in the Research in Arthritis in Canadian Children Emphasizing Outcomes (ReACCh-Out) and the Canadian Alliance of Pediatric Rheumatology Investigators Registry (CAPRI) cohorts were included. Cumulative incidences of drug starts and outcome attainment within 70 weeks of diagnosis were compared with Kaplan Meier survival analysis and multivariable Cox regression.

RESULTS

The 2005-2010 and 2017-2021 cohorts included 1128 and 721 patients, respectively. JIA category distribution and baseline clinical juvenile idiopathic arthritis disease activity (cJADAS10) scores at enrolment were comparable. By 70 weeks, 6% of patients (95% CI 5, 7) in the 2005-2010 and 26% (23, 30) in the 2017-2021 cohort had started a biologic DMARD (bDMARD), and 43% (40, 47) and 60% (56, 64) had started a conventional DMARD (cDMARD), respectively. Outcome attainment was 64% (61, 67) and 83% (80, 86) for Inactive disease (Wallace criteria), 69% (66, 72) and 84% (81, 87) for minimally active disease (cJADAS10 criteria), 57% (54, 61) and 63% (59, 68) for pain control (<1/10), and 52% (47, 56) and 54% (48, 60) for a good health-related quality of life.

CONCLUSION

Although baseline disease characteristics were comparable in the 2005-2010 and 2017-2021 cohorts, cDMARD and bDMARD use increased with a concurrent increase in minimally active and inactive disease. Improvements in parent and patient reported outcomes were smaller than improvements in disease activity.

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.

A comparison of Juvenile Idiopathic Arthritis classification systems with the Research in Arthritis in Canadian Children, Emphasizing Outcomes (ReACCh-Out) cohort

OBJECTIVE

To compare International League of Associations for Rheumatology (ILAR) and Paediatric Rheumatology INternational Trials Organisation (PRINTO) classifications for juvenile idiopathic arthritis (JIA) using data from the Research in Arthritis in Canadian Children emphasizing Outcomes cohort (ReACCh-Out). The aim of the PRINTO classification, still in development, is to identify homogeneous groups of patients with JIA.

METHODS

We used data recorded within 7 months of diagnosis in 1228 patients to assign patients according to the two classification systems by computation. We compared the proportions of patient classified and the alignment of classified categories with clinical-biological subtypes and adult types of arthritis.

RESULTS

The PRINTO system classified 244 patients (19.9%) as Early-onset ANA-positive (EOANA), 157 (12.8%) as Enthesitis/Spondylitis-related, 38 (3.1%) as Systemic, and 10 (0.8%) as RF-positive JIA. Twelve percent of patients were unclassifiable using ILAR while 63.3% were unclassifiable using PRINTO criteria (777 Other JIA and 2 Unclassified JIA). In sensitivity analyses, >50% remained unclassifiable by PRINTO. ILAR categories aligned better with clinical-biological subtypes in 131 patients (χ² =44, p=0.005 versus χ² =15, p=0.07 for PRINTO), and with adult types of arthritis in 389 evaluable patients.

CONCLUSION

Current identified PRINTO disorders classify a minority of patients with JIA, leaving a large proportion with Other disorders requiring further characterization. Current PRINTO classifications do not appear to improve alignment with clinical-biological subtypes or adult forms of arthritis relative to the older ILAR system.

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.

Teens Taking Charge: A Randomized Controlled Trial of a Web-Based Self-Management Program With Telephone Support for Adolescents With Juvenile Idiopathic Arthritis

Background

Juvenile idiopathic arthritis (JIA) is a serious and potentially debilitating pediatric illness. Improved disease self-management may help to improve health outcomes.

Objective

This study aimed to evaluate the effectiveness of the Teens Taking Charge Web-based self-management intervention in reducing symptoms and improving health-related quality of life (HRQL) in adolescents with JIA compared with a Web-based education control condition.

Methods

Adolescents with JIA aged 12 to 18 years were recruited from 11 Canadian pediatric rheumatology centers. Caregivers were invited to participate along with their child. In addition to standard medical care, participants were randomized to receive either (1) the Teens Taking Charge self-management intervention or (2) a Web-based education control condition for a period of 12 weeks. Adolescents in the intervention group completed website modules addressing cognitive behavioral coping skills, stress management, and other self-management topics, while also receiving monthly telephone calls from a trained health coach. Adolescents in the education control group were instructed to view a series of preselected public JIA educational websites and received monthly calls from a coach who asked about their own best efforts at managing JIA. Caregivers in the intervention group completed website modules related to promoting independence and disease self-management in their child. Caregivers in the education control group were instructed to view a series of preselected public JIA educational websites. Outcome assessment occurred at baseline, 12 weeks (posttreatment), and at 6 and 12 months postrandomization. The primary outcomes were pain intensity, pain interference, and HRQL. Secondary outcomes were emotional symptoms, adherence, coping, knowledge, and self-efficacy.

Results

In total, 333 adolescents and 306 caregivers were enrolled. Significant overall reductions in pain intensity (P=.02) and pain interference (P=.007) were observed for intervention group participants compared with those in the education control group, after adjusting for baseline levels. There was a significant overall improvement in HRQL related to problems with pain (P=.02) and problems with daily activities (P=.01). There was also a significant difference in the intervention group over time (P=.008) for HRQL related to treatment problems, with the intervention group participants demonstrating improved HRQL by 12 months compared with education control group participants. Both groups showed nonsignificant improvements compared with baseline in other primary outcomes. There were no significant differences between the groups in any secondary outcomes or caregiver-reported outcomes.

Conclusions

The results of this randomized trial suggest that the Teens Taking Charge Web-based intervention is effective at reducing both pain intensity and pain interference, as well as improving HRQL in adolescents with JIA, compared with education control. These effects are sustained for up to 12 months following program completion. The Teens Taking Charge program is now publicly available at no cost.

Trial Registration

ClinicalTrials.gov NCT01572896; https://clinicaltrials.gov/ct2/show/NCT01572896

Prospective Determination of the Incidence and Risk Factors of New-Onset Uveitis in Juvenile Idiopathic Arthritis: The Research in Arthritis in Canadian Children Emphasizing Outcomes Cohort

OBJECTIVE

Identification of the incidence of juvenile idiopathic arthritis (JIA)-associated uveitis and its risk factors is essential to optimize early detection. Data from the Research in Arthritis in Canadian Children Emphasizing Outcomes inception cohort were used to estimate the annual incidence of new-onset uveitis following JIA diagnosis and to identify associated risk factors.

METHODS

Data were reported every 6 months for 2 years, then yearly to 5 years. Incidence was determined by Kaplan-Meier estimators with time of JIA diagnosis as the reference point. Univariate log-rank analysis identified risk factors and Cox regression determined independent predictors.

RESULTS

In total, 1,183 patients who enrolled within 6 months of JIA diagnosis met inclusion criteria, median age at diagnosis of 9.0 years (interquartile range [IQR] 3.8-12.9), median follow-up of 35.2 months (IQR 22.7-48.3). Of these patients, 87 developed uveitis after enrollment. The incidence of new-onset uveitis was 2.8% per year (95% confidence interval [95% CI] 2.0-3.5) in the first 5 years. The annual incidence decreased during follow-up but remained at 2.1% (95% CI 0-4.5) in the fifth year, although confidence intervals overlapped. Uveitis was associated with young age (<7 years) at JIA diagnosis (hazard ratio [HR] 8.29, P < 0.001), positive antinuclear antibody (ANA) test (HR 3.20, P < 0.001), oligoarthritis (HR 2.45, P = 0.002), polyarthritis rheumatoid factor negative (HR 1.65, P = 0.002), and female sex (HR 1.80, P = 0.02). In multivariable analysis, only young age at JIA diagnosis and ANA positivity were independent predictors of uveitis.

CONCLUSION

Vigilant uveitis screening should continue for at least 5 years after JIA diagnosis, and priority for screening should be placed on young age (<7 years) at JIA diagnosis and a positive ANA test.

Predicting Which Children with Juvenile Idiopathic Arthritis Will Not Attain Early Remission with Conventional Treatment: Results from the ReACCh-Out Cohort

OBJECTIVE

To estimate the probability of early remission with conventional treatment for each child with juvenile idiopathic arthritis (JIA). Children with a low chance of remission may be candidates for initial treatment with biologics or triple disease-modifying antirheumatic drugs (DMARD).

METHODS

We used data from 1074 subjects in the Research in Arthritis in Canadian Children emphasizing Outcomes (ReACCh-Out) cohort. The predicted outcome was clinically inactive disease for ≥ 6 months starting within 1 year of JIA diagnosis in patients who did not receive early biologic agents or triple DMARD. Models were developed in 200 random splits of 75% of the cohort and tested on the remaining 25% of subjects, calculating expected and observed frequencies of remission and c-index values.

RESULTS

Our best Cox logistic model combining 18 clinical variables a median of 2 days after diagnosis had a c-index of 0.69 (95% CI 0.67-0.71), better than using JIA category alone (0.59, 95% CI 0.56-0.63). Children in the lowest probability decile had a 20% chance of remission and 21% attained remission; children in the highest decile had a 69% chance of remission and 73% attained remission. Compared to 5% of subjects identified by JIA category alone, the model identified 14% of subjects as low chance of remission (probability < 0.25), of whom 77% failed to attain remission.

CONCLUSION

Although the model did not meet our a priori performance threshold (c-index > 0.70), it identified 3 times more subjects with low chance of remission than did JIA category alone, and it may serve as a benchmark for assessing value added by future laboratory/imaging biomarkers.

Health-Related Quality of Life in an Inception Cohort of Children With Juvenile Idiopathic Arthritis: A Longitudinal Analysis

OBJECTIVE

To describe changes in health-related quality of life (HRQoL) over time in children with juvenile idiopathic arthritis (JIA), relative to other outcomes, and to identify predictors of unfavorable HRQoL trajectories.

METHODS

Children with JIA in the Research in Arthritis in Canadian Children emphasizing Outcomes (ReACCh-Out) cohort were included. The Juvenile Arthritis Quality of Life Questionnaire (JAQQ, a standardized instrument), health-related Quality of My Life (HRQoML, an instrument based on personal valuations), and JIA core variables were completed serially. Analyses included median values, Kaplan-Meier survival curves, and latent trajectory analysis.

RESULTS

A total of 1,249 patients enrolled at a median of 0.5 months after diagnosis were followed for a median of 34.2 months. The degree of initial HRQoL impairment and probabilities of reaching the best possible HRQoL scores varied across JIA categories (best for oligoarthritis, worst for rheumatoid factor-positive polyarthritis). Median times to attain best possible HRQoL scores (JAQQ 59.3 months, HRQoML 34.5 months), lagged behind those for disease activity, pain, and disability measures. Most patients followed trajectories with minimal or mild impairment; however, 7.6% and 13.8% of patients, respectively, followed JAQQ and HRQoML trajectories with persistent major impairment in HRQoL. JIA category, aboriginal ethnicity, and baseline disease activity measures distinguished between membership in trajectories with major and minimal impairments.

CONCLUSION

Improvement in HRQoL is slower than for disease activity, pain, and disability. Improvement of a measure based on respondents' preferences (HRQoML) is more rapid than that of a standardized measure (JAQQ). Higher disease activity at diagnosis heralds an unfavorable HRQoL trajectory.

Growth and weight gain in children with juvenile idiopathic arthritis: results from the ReACCh-Out cohort

BACKGROUND

With modern treatments, the effect of juvenile idiopathic arthritis (JIA) on growth may be less than previously reported. Our objective was to describe height, weight and body mass index (BMI) development in a contemporary JIA inception cohort.

METHODS

Canadian children newly-diagnosed with JIA 2005-2010 had weight and height measurements every 6 months for 2 years, then yearly up to 5 years. These measurements were used to calculate mean age- and sex-standardized Z-scores, and estimate prevalence and cumulative incidence of growth impairments, and the impact of disease activity and corticosteroids on growth.

RESULTS

One thousand one hundred forty seven children were followed for median 35.5 months. Mean Z-scores, and the point prevalence of short stature (height < 2.5th percentile, 2.5% to 3.4%) and obesity (BMI > 95th percentile, 15.8% to 16.4%) remained unchanged in the whole cohort. Thirty-three children (2.9%) developed new-onset short stature, while 27 (2.4%) developed tall stature (>97.5th percentile). Children with systemic arthritis (n = 77) had an estimated 3-year cumulative incidence of 9.3% (95%CI: 4.3-19.7) for new-onset short stature and 34.4% (23-49.4) for obesity. Most children (81.7%) received no systemic corticosteroids, but 1 mg/Kg/day prednisone-equivalent maintained for 6 months corresponded to a drop of 0.64 height Z-scores (0.56-0.82) and an increase of 0.74 BMI Z-scores (0.56-0.92). An increase of 1 in the 10-cm physician global assessment of disease activity maintained for 6 months corresponded to a drop of 0.01 height Z-scores (0-0.02).

CONCLUSIONS

Most children in this modern JIA cohort grew and gained weight as children in the general population. About 1 in 10 children who had systemic arthritis, uncontrolled disease and/or prolonged corticosteroid use, had increased risk of growth impairment.

Malignancy in Pediatric-onset Systemic Lupus Erythematosus

OBJECTIVE

To determine cancer incidence in a large pediatric-onset systemic lupus erythematosus (SLE) population.

METHODS

Data were examined from 12 pediatric SLE registries in North America. Patients were linked to their regional cancer registries to detect cancers observed after cohort entry, defined as date first seen in the clinic. The expected number of malignancies was obtained by multiplying the person-years in the cohort (defined from cohort entry to end of followup) by the geographically matched age-, sex-, and calendar year-specific cancer rates. The standardized incidence ratio (SIR; ratio of cancers observed to expected) was generated, with 95% CI.

RESULTS

A total of 1168 patients were identified from the registries. The mean age at cohort entry was 13 years (SD 3.3), and 83.7% of the subjects were female. The mean duration of followup was 7.6 years, resulting in a total observation period of 8839 years spanning the calendar period 1974-2009. During followup, fourteen invasive cancers occurred (1.6 cancers per 1000 person-yrs, SIR 4.13, 95% CI 2.26-6.93). Three of these were hematologic (all lymphomas), resulting in an SIR for hematologic cancers of 4.68 (95% CI 0.96-13.67). SIR were increased for both male and female patients, and across age groups.

CONCLUSION

Although cancer remains a relatively rare outcome in pediatric-onset SLE, our data do suggest an increase in cancer for patients followed an average of 7.6 years. About one-fifth of the cancers were hematologic. Longer followup, and study of drug effects and disease activity, is warranted.

Validation of administrative case ascertainment algorithms for chronic childhood arthritis in Manitoba, Canada

We validated case ascertainment algorithms for juvenile idiopathic arthritis (JIA) in the provincial health administrative databases of Manitoba, Canada. A population-based pediatric rheumatology clinical database from April 1st 1980 to March 31st 2012 was used to test case definitions in individuals diagnosed at ≤15 years of age. The case definitions varied the number of diagnosis codes (1, 2, or 3), time frame (1, 2 or 3 years), time between diagnoses (ever, >1 day, or ≥8 weeks), and physician specialty. Positive predictive value (PPV), sensitivity, and specificity with 95% confidence intervals (CIs) are reported. A case definition of 1 hospitalization or ≥2 diagnoses in 2 years by any provider ≥8 weeks apart using diagnosis codes for rheumatoid arthritis and ankylosing spondylitis produced a sensitivity of 89.2% (95% CI 86.8, 91.6), specificity of 86.3% (95% CI 83.0, 89.6), and PPV of 90.6% (95% CI 88.3, 92.9) when seronegative enthesopathy and arthropathy (SEA) was excluded as JIA; and sensitivity of 88.2% (95% CI 85.7, 90.7), specificity of 90.4% (95% CI 87.5, 93.3), and PPV of 93.9% (95% CI 92.0, 95.8) when SEA was included as JIA. This study validates case ascertainment algorithms for JIA in Canadian administrative health data using diagnosis codes for both rheumatoid arthritis (RA) and ankylosing spondylitis, to better reflect current JIA classification than codes for RA alone. Researchers will be able to use these results to define cohorts for population-based studies.

Malignancy incidence in 5294 patients with juvenile arthritis

Objective

To determine cancer incidence in a large clinical juvenile-onset arthritis population.

Methods

We combined data from 6 existing North American juvenile-onset arthritis cohorts. Patients with juvenile-onset arthritis were linked to regional cancer registries to detect incident cancers after cohort entry, defined as first date seen in the paediatric rheumatology clinic. The expected number of malignancies was obtained by multiplying the person-years observed (defined from cohort entry to end of follow-up) by the geographically matched age, sex and calendar year-specific cancer rates. The standardised incidence ratios (SIR; ratio of cancers observed to expected) were generated, with 95% CIs.

Results

The 6 juvenile arthritis registries provided a total of 5294 patients. The mean age at cohort entry was 8.9 (SD 5.0) years and 68% of participants were female. The mean duration of follow-up was 6.8 years with a total of 36 063 person-years spanning 1978–2012. During follow-up, 9 invasive cancers occurred, compared with 10.9 expected (SIR 0.82, 95% CI 0.38 to 1.5). 3 of these were haematological (Hodgkin's, non-Hodgkin's lymphoma and leukaemia). 6 of the patients with cancer were exposed to disease-modifying drugs; 5 of these had also been exposed to biological agents.

Conclusions

We did not clearly demonstrate an increase in overall malignancy risk in patients with juvenile-onset arthritis followed for an average of almost 7 years. 3 of the 9 observed cancers were haematological. 5 of the cancers arose in children exposed to biological agents. Longer follow-up of this population is warranted, with further study of drug effects.

Incident Vertebral Fractures and Risk Factors in the First Three Years Following Glucocorticoid Initiation Among Pediatric Patients With Rheumatic Disorders

Vertebral fractures are an important yet underrecognized manifestation of osteoporosis in children with chronic, glucocorticoid-treated illnesses. Our goal was to determine the incidence and clinical predictors of vertebral fractures in the 3 years following glucocorticoid initiation among pediatric patients with rheumatic disorders. Incident vertebral fractures were evaluated according to the Genant semiquantitative method on lateral radiographs at baseline and then annually in the 3 years following glucocorticoid initiation. Extended Cox models were used to assess the association between vertebral fractures and clinical risk predictors. A total of 134 children with rheumatic disorders were enrolled in the study (mean ± standard deviation (SD) age 9.9 ± 4.4 years; 65% girls). The unadjusted vertebral fracture incidence rate was 4.4 per 100 person-years, with a 3-year incidence proportion of 12.4%. The highest annual incidence occurred in the first year (6.0%; 95% confidence interval (CI) 2.9% to 11.7%). Almost one-half of the patients with fractures were asymptomatic. Every 0.5 mg/kg increase in average daily glucocorticoid (prednisone equivalents) dose was associated with a twofold increased fracture risk (hazard ratio (HR) 2.0; 95% CI 1.1 to 3.5). Other predictors of increased vertebral fracture risk included: (1) increases in disease severity scores between baseline and 12 months; (2) increases in body mass index Z-scores in the first 6 months of each 12-month period preceding the annual fracture assessment; and (3) decreases in lumbar spine bone mineral density Z-scores in the first 6 months of glucocorticoid therapy. As such, we observed that a clinically significant number of children with rheumatic disorders developed incident vertebral fractures in the 3 years following glucocorticoid initiation. Almost one-half of the children were asymptomatic and thereby would have been undiagnosed in the absence of radiographic monitoring. In addition, discrete clinical predictors of incident vertebral fractures were evident early in the course of glucocorticoid therapy.

The risk and nature of flares in juvenile idiopathic arthritis: results from the ReACCh-Out cohort

OBJECTIVE

To describe probabilities and characteristics of disease flares in children with juvenile idiopathic arthritis (JIA) and to identify clinical features associated with an increased risk of flare.

METHODS

We studied children in the Research in Arthritis in Canadian Children emphasizing Outcomes (ReACCh-Out) prospective inception cohort. A flare was defined as a recurrence of disease manifestations after attaining inactive disease and was called significant if it required intensification of treatment. Probability of first flare was calculated with Kaplan-Meier methods, and associated features were identified using Cox regression.

RESULTS

1146 children were followed up a median of 24 months after attaining inactive disease. We observed 627 first flares (54.7% of patients) with median active joint count of 1, physician global assessment (PGA) of 12 mm and duration of 27 weeks. Within a year after attaining inactive disease, the probability of flare was 42.5% (95% CI 39% to 46%) for any flare and 26.6% (24% to 30%) for a significant flare. Within a year after stopping treatment, it was 31.7% (28% to 36%) and 25.0% (21% to 29%), respectively. A maximum PGA >30 mm, maximum active joint count >4, rheumatoid factor (RF)-positive polyarthritis, antinuclear antibodies (ANA) and receiving disease-modifying antirheumatic drugs (DMARDs) or biological agents before attaining inactive disease were associated with increased risk of flare. Systemic JIA was associated with the lowest risk of flare.

CONCLUSIONS

In this real-practice JIA cohort, flares were frequent, usually involved a few swollen joints for an average of 6 months and 60% led to treatment intensification. Children with a severe disease course had an increased risk of flare.

Description of active joint count trajectories in juvenile idiopathic arthritis

OBJECTIVE

To describe the trajectories of longitudinal joint disease activity in juvenile idiopathic arthritis (JIA), and to examine associations of clinical and laboratory characteristics with the identified trajectories.

METHODS

A retrospective cohort study at 2 Canadian centers was performed. The longitudinal trajectories of active joint counts were described in a proof-of-concept study using a latent growth curve analysis. Baseline patient characteristics were compared across trajectory groups.

RESULTS

Data were analyzed on 659 children diagnosed with JIA between March 1980 and September 2009. The median age at diagnosis was 10.0 years (interquartile range 3.7-13.4) and 61% (402/659) were female. The International League of Associations for Rheumatology (ILAR) diagnoses were as follows: oligoarthritis (36%), enthesitis-related arthritis (20%), rheumatoid factor (RF)-negative polyarthritis (13%), undifferentiated arthritis (12%), psoriatic arthritis (8%), systemic arthritis (7%), and RF-positive polyarthritis (4%). Based on the trajectories of their active joint counts, the 659 patients were each classified in 1 of 5 latent classes (which can be described as high decreasing, moderate increasing, persistent moderate, persistent low, and minimal joint activity). These latent classes were clinically and statistically distinct from the ILAR categories.

CONCLUSION

In this proof-of-concept study, in which we used an analytic methodology in a novel way, we identified 5 clinically and statistically distinct trajectories of disease course. The subsets of patients within each class were different from those described by the ILAR classification criteria. This successful application of this method supports its use in a chronic disease with a fluctuating course such as JIA. These methods should be expanded for the purposes of predictive modeling.

What matters most for patients, parents, and clinicians in the course of juvenile idiopathic arthritis? A qualitative study

OBJECTIVE

To assess which clinical features are most important for patients, parents, and clinicians in the course of juvenile idiopathic arthritis (JIA).

METHODS

Forty-nine people participated in 6 audience-specific focus group discussions and 112 reciprocal interviews in 3 Canadian cities. Participants included youth with JIA, experienced English- and French-speaking parents, novice parents (<6 mos since diagnosis), pediatric rheumatologists, and allied health professionals. Participants discussed the importance of 34 JIA clinical features extracted from medical literature. Transcripts and interview reports underwent qualitative analysis to establish relative priorities for each group.

RESULTS

Most study participants considered medication requirements, medication side effects, pain, participant-defined quality of life, and active joints as high priority clinical features of JIA. Active joint count was the only American College of Rheumatology core variable accorded high or medium priority by all groups. Rheumatologists and allied health professionals considered physician global assessment as high priority, but it had very low priority for patients and parents. The parent global assessment was considered high priority by clinicians, medium to high by parents, and low by patients. Child Health Assessment Questionnaire scores were considered low priority by patients and parents, and moderate or high by clinicians. The number of joints with limited motion was given low to very low priority by all groups. Parents gave high priority to arthritis flares.

CONCLUSION

If our findings are confirmed, medication requirements, medication side effects, pain, participant-defined quality of life, and active joint counts should figure prominently in describing the course of JIA.

The outcomes of juvenile idiopathic arthritis in children managed with contemporary treatments: results from the ReACCh-Out cohort

OBJECTIVE

To describe clinical outcomes of juvenile idiopathic arthritis (JIA) in a prospective inception cohort of children managed with contemporary treatments.

METHODS

Children newly diagnosed with JIA at 16 Canadian paediatric rheumatology centres from 2005 to 2010 were included. Kaplan-Meier survival curves for each JIA category were used to estimate probability of ever attaining an active joint count of 0, inactive disease (no active joints, no extraarticular manifestations and a physician global assessment of disease activity <10 mm), disease remission (inactive disease >12 months after discontinuing treatment) and of receiving specific treatments.

RESULTS

In a cohort of 1104 children, the probabilities of attaining an active joint count of 0 exceeded 78% within 2 years in all JIA categories. The probability of attaining inactive disease exceeded 70% within 2 years in all categories, except for RF-positive polyarthritis (48%). The probability of discontinuing treatment at least once was 67% within 5 years. The probability of attaining remission within 5 years was 46-57% across JIA categories except for polyarthritis (0% RF-positive, 14% RF-negative). Initial treatment included joint injections and non-steroidal anti-inflammatory drugs for oligoarthritis, disease-modifying antirheumatic drugs (DMARDs) for polyarthritis and systemic corticosteroids for systemic JIA.

CONCLUSIONS

Most children with JIA managed with contemporary treatments attain inactive disease within 2 years of diagnosis and many are able to discontinue treatment. The probability of attaining remission within 5 years of diagnosis is about 50%, except for children with polyarthritis.

The development of bone mineral lateralization in the arms

Bone mineral content (BMC) is known to be greater in the dominant arm after the age of 8 years. We studied a group of children and found that BMC sidedness gradually increased up to the age of 6 years and then remained stable into late adolescence.

INTRODUCTION

Bone mineral content (BMC) exhibits sidedness in the arms after the age of 8 years, but it is not known whether BMC is greater in the dominant arm from birth or whether lateralization develops in early childhood. To address this, we examined bone mineral status in relation to handedness and age.

METHODS

Subjects (N = 158) were children recently initiating glucocorticoids for underlying disease (leukemia 43 %, rheumatic conditions 39 %, nephrotic syndrome 18 %). Handedness was determined by questionnaire and BMC by dual-energy X-ray absorptiometry.

RESULTS

Median age was 7.2 years (range, 1.5 to 17.0 years), 49 % was male, and the spine BMD Z-score was -0.9 (SD, 1.3). By linear regression, BMC sidedness in the arms was significantly related to age (r = 0.294, p = 0.0005). Breakpoint analysis revealed two lines with a knot at 6.0 years (95 % CI, 4.5-7.5 years). The formula for the first line was: dominant:nondominant arm BMC ratio = 0.029 × age [in years] + 0.850 (r = 0.323, p = 0.017). The slope of the second line was not different from 0 (p = 0.332), while the slopes for the two lines were significantly different (p = 0.027).

CONCLUSIONS

These results show that arm BMC sidedness in this patient group develops up to age 6 years and then remains stable into late adolescence. This temporal profile is consistent with mechanical stimulation of the skeleton in response to asymmetrical muscle use as handedness becomes manifest.

Incident vertebral fractures among children with rheumatic disorders 12 months after glucocorticoid initiation: a national observational study

OBJECTIVE

To determine the frequency of incident vertebral fractures (IVF) 12 months after glucocorticoid (GC) initiation in children with rheumatic diseases and to identify children at higher risk.

METHODS

Children with rheumatic diseases initiating GC were enrolled in a prospective observational study. Annual spine radiographs were evaluated using the Genant semiquantitative method. Spine areal bone mineral density (aBMD) was measured every 6 months. Clinical features, including cumulative GC dose, back pain, disease and physical activity, calcium and vitamin D intake, and spine aBMD Z scores, were analyzed for association with IVF.

RESULTS

Seven (6%) of 118 children (95% confidence interval 2.9-11.7%) had IVF. Their diagnoses were: juvenile dermatomyositis (n = 2), systemic lupus erythematosus (n = 3), systemic vasculitis (n = 1), and mixed connective tissue disease (n = 1). One child was omitted from the analyses after 4 months because of osteoporosis treatment for symptomatic IVF. Children with IVF received on average 50% more GC than those without (P = 0.030), had a greater increase in body mass index (BMI) at 6 months (P = 0.010), and had greater decrements in spine aBMD Z scores in the first 6 months (P = 0.048). Four (67%) of 6 children with IVF and data to 12 months had spine aBMD Z scores less than -2.0 at 12 months compared to 16% of children without IVF (P = 0.011).

CONCLUSION

The incidence of VF 12 months following GC initiation was 6%; most children were asymptomatic. Children with IVF received more GC, had greater increases in BMI, and had greater declines in spine aBMD Z scores in the first 6 months.

Factors associated with a longer time to access pediatric rheumatologists in Canadian children with juvenile idiopathic arthritis

OBJECTIVE

The Research on Arthritis in Canadian Children Emphasizing Outcomes (ReACCh Out) cohort is a prospective inception cohort of patients with newly diagnosed juvenile idiopathic arthritis (JIA) seen in 16 Canadian pediatric rheumatology (PR) centers. We used data from this cohort to explore factors associated with longer time from symptom onset to the first visit to (PR), and with longer time from first visit to a diagnosis of JIA.

METHODS

We included children enrolled in ReACCh Out within 6 months of JIA diagnosis, for whom the dates of symptom onset and first PR visit were recorded. We used Cox proportional hazard modeling to investigate the effects of history, physical examination, and laboratory evaluation on the interval from JIA symptom onset to first PR assessment.

RESULTS

In total, 319 children from the cohort were included. Having a fever (hazard ratio 1.80, 95% CI 1.10, 2.93), any part South Asian ethnicity (HR 1.75, 95% CI 1.04, 2.95), highly educated parents (HR 1.69, 95% CI 1.18, 2.44), and limp (HR 1.55, 95% 1.16, 2.06) were significantly associated with shorter time from symptom onset to first PR assessment, while a history of heel pain or enthesitis (HR 0.61, 95% 0.38, 0.97) was significantly associated with a longer time to first PR visit.

CONCLUSION

Children with a history of a fever, limp, any part South Asian ethnicity, or highly educated parents were more likely to see PR sooner than patients without these features, while children with a history of enthesitis received PR care later than those without enthesitis.

Familial seropositive rheumatoid arthritis in North American Native families: effects of shared epitope and cytokine genotypes

OBJECTIVE

A number of North American native (NAN) populations have high prevalence rates of both rheumatoid arthritis (RA) and the shared epitope (SE). We examined the phenotype and familial incidence of RA in a NAN population, and investigated how the SE and cytokine genes may affect disease risk within affected families.

METHODS

NAN patients with seropositive RA or polyarthritis rheumatoid factor (RF) positive juvenile idiopathic arthritis (JIA) were identified from clinical databases. Patients were recruited consecutively as they presented for clinic visits. Family pedigrees were constructed and consenting relatives were interviewed and examined. The risk of RA within families was calculated by multiple logistic regression. Input variables were the SE and cytokine genotypes. Probands and affected relatives were entered as the affected group, and unaffected relatives within families as the unaffected group. Results were confirmed among unrelated subjects, i.e., unrelated patients and unaffected relatives of other probands.

RESULTS

The familial prevalence of RA was 0.50 (95% confidence intervals 0.30, 0.70) among 28 families studied. The interleukin 10 (IL-10) promoter -1082 G/A genotype decreased the odds of RA relative to the A/A genotype in affected families (OR 0.247, 95% CI 0.081, 0.751; p = 0.014) and among unrelated subjects (OR 0.203, 95% CI 0.064, 0.640; p = 0.006). The G/G genotype yielded an OR of 0.093 (95% 0.013, 0.676; p = 0.019) among unrelated subjects. The SE had no effect in these calculations.

CONCLUSION

There was a high familial prevalence of RA in this NAN cohort. In susceptible NAN families, the risk of RA was reduced by IL-10 genotypes, whereas the SE did not affect risk. Study of healthy NAN controls is required to determine if these conclusions apply to this NAN population as a whole.

Cytokine genotypes correlate with pain and radiologically defined joint damage in patients with juvenile rheumatoid arthritis

OBJECTIVES

Single nucleotide polymorphisms (SNPs) in cytokine genes have been associated with risk of a number of autoimmune diseases. Moreover, some SNPs are associated with variations in rates of in vitro gene expression, and it is therefore possible that these functional polymorphisms may differentially affect inflammatory processes and disease outcome. This project's objective was to determine whether cytokine genotypes correlate with disease outcomes in patients with juvenile rheumatoid arthritis (JRA).

METHODS

Genotypes of SNPs of pro-inflammatory cytokines, tumour necrosis factor-alpha -308G -->A, interleukin-6 (IL-6) -174G -->C and interferon-gamma +874G -->A, and anti-inflammatory, immunosuppressive cytokines, interleukin-10 -1082G -->A, -819C -->T and -592A -->C and transforming growth factor-beta1 (TGF-beta1) codon 10T -->C and codon 25G -->C, were determined for patients with JRA who previously participated in a long-term outcome study. Cytokine genotypes and clinical variables showing significant correlations with clinical outcomes at the alpha = 0.100 level in univariate analyses were entered in multivariate tests.

RESULTS

In multivariate tests, the IL-6 genotype -174G/G was positively correlated with pain [regression coefficient B = 0.899, 95% confidence intervals (CI) 0.185, 1.612, P = 0.014]. The homozygous TGF-beta1 codon 25G/G genotype showed a protective effect against joint space narrowing on radiographs taken within 2 yr of disease onset, but confidence intervals were wide [odds ratio (OR) 0.176, 95% CI 0.037, 0.837 P = 0.029].

CONCLUSIONS

The correlation of IL-6 genotype with pain and the possible association of the TGF-beta1 codon 25 genotype with short-term radiographic damage (G/C with greater risk and G/G with decreased risk) suggests that both these polymorphisms may be useful early prognostic indicators. Further studies of the relation between cytokine genotypes and outcomes in patients with all forms of juvenile idiopathic arthritis (JIA) are warranted.

Predictors of pain in children with established juvenile rheumatoid arthritis

OBJECTIVE

To examine demographic and disease-related variables that affect pain in a large cohort of patients with juvenile rheumatoid arthritis (JRA).

METHODS

Selection criteria were an onset of JRA >/=5 years prior to study and age >/=8 years at the time of the study. Pain was measured by a self-administered 10-cm visual analog scale. Possible explanatory variables studied included age at study, sex, race, onset subtype, active disease duration, active joint count, and physician's global assessment (PGA).

RESULTS

In a multiple regression model, active disease duration, PGA, and age at study were independent predictors explaining 22% of the variation in pain scores. Stratified analyses showed an effect of age in the 8-15-year group, but not in older patients.

CONCLUSION

Disease-related factors explain only a small proportion of the variation in pain scores. Age has an effect on pain scores only in younger patients. The role of other factors, including psychosocial factors, needs further study.

Radiologic outcome and its relationship to functional disability in juvenile rheumatoid arthritis

OBJECTIVE

To determine the radiologic outcome in juvenile rheumatoid arthritis (JRA) and the relationship of radiologically detected joint damage to functional disability using multivariate analyses.

METHODS

Selection criteria included a diagnosis of JRA made by 1977 American College of Rheumatology criteria, onset of arthritis > or = 5 years prior to study, current age > or = 8 years, a minimum grade 3 reading ability, and the availability of radiographs. Disability was measured by the Childhood Health Assessment Questionnaire (CHAQ) and Steinbrocker classifications. Radiographs taken within 2 years after onset (early) and the most recent radiographs (late) were examined by a single pediatric radiologist blinded to patients' identities, diagnoses, and outcomes. Multiple regression analyses were performed.

RESULTS

On late radiographs the frequencies of joint space narrowing were 38, 14, 43, and 79%, respectively, among patients with systemic, pauciarticular, rheumatoid factor (RF) negative polyarticular, and RF positive polyarticular onset; erosions occurred in 63, 25, 39, and 75%, respectively. Early erosions were most frequent in patients with RF+ polyarticular onset, while both joint space narrowing and erosions occurred early in systemic onset. Radiologic signs of joint damage were most frequent at hips and wrists, while knees and ankles were relatively spared. Based on patients who had radiographs performed within one year of clinical study, 17.7% of the variation in CHAQ score was explained by joint space narrowing, 32.4% by pain, and 5% by a severe rating on physician's global estimate of disease activity. The odds of a Steinbrocker class > I were increased by joint space narrowing, pain, systemic onset, and active joint count.

CONCLUSION

Differences in the frequencies and patterns of joint damage occur both among JRA onset subtypes and among individual joints. Radiographic damage, especially joint space narrowing, correlates with functional disability. However, pain is the major contributor to variation in CHAQ scores.

Early predictors of longterm outcome in patients with juvenile rheumatoid arthritis: subset-specific correlations

OBJECTIVE

To determine early predictors of longterm outcome in juvenile rheumatoid arthritis (JRA) in a multicenter cohort.

METHODS

Patients were selected if they were > or = 8 years of age; the onset of arthritis occurred > or = 5 years before study; and a diagnosis of JRA was made at a participating center. Outcome variables were scores on self-administered Childhood Health Assessment Questionnaires (CHAQ) and active disease duration. Possible explanatory variables assessed included characteristics present at onset, HLA alleles, in particular the rheumatoid arthritis associated shared epitope (RASE), and radiographic indicators of joint damage within 2 years of onset. Data for 393 patients were available. Multivariate analyses were performed for the total group and for each onset subtype.

RESULTS

Male sex correlated with worse disability in systemic onset JRA but less disability in RF negative, and a shorter active disease duration in RF positive polyarticular onset JRA. Positive antinuclear antibody correlated with a longer active disease duration in patients with pauciarticular onset JRA. Younger age at onset predicted longer active disease duration in pauciarticular and RF negative polyarticular, and a shorter active disease duration in systemic onset JRA. Residence on a reserve, rather than native North American race, correlated with worse disability. The RASE correlated with less disability in systemic JRA; but no correlation with outcome was evident for patients with rheumatoid factor positive polyarticular JRA.

CONCLUSION

Variables predictive of longterm outcome in JRA are specific for each onset subtype. The most important early predictors were age at onset and sex of the patient. Place of residence may have a greater effect on disability than race. RASE may associate with a more favorable outcome in systemic onset disease.

Disease course and outcome of juvenile rheumatoid arthritis in a multicenter cohort

OBJECTIVE

To determine the disease course and outcome in a multicenter cohort of patients with juvenile rheumatoid arthritis (JRA).

METHODS

All patients with JRA seen at 3 pediatric rheumatology centers were identified from databases and/or clinic records. Inclusion criteria were a diagnosis of JRA (1977 American College of Rheumatology criteria), a followup period of at least 5 years since onset, and a minimum age of 8 years. Patients were examined and completed a Childhood Health Assessment Questionnaire (CHAQ). Kaplan-Meier curves were constructed to estimate rates of remission, relapse, and arthroplasty. Remission was defined as absence of active arthritis while off treatment for at least 2 years. Outcome measures were active disease duration, CHAQ scores, pain determined by visual analog scales, physician's global assessments, and Steinbrocker functional classifications. Years of education and employment status were ascertained.

RESULTS

We studied 392 patients of 652 (60%) who met the selection criteria. The probabilities of remission at 10 years after onset were 37, 47, 23, and 6% for patients with systemic, pauciarticular, RF- polyarticular, and RF+ polyarticular JRA, respectively. The probability of relapse varied from 30 to 100% at 15 years. The probability of arthroplasty varied from 13 to 57% after 15 years of active disease. We found 2.5% of patients assessed were in Steinbrocker Classes III or IV and 6% were in the highest CHAQ score (> 1.5) group. Compared with national statistics, fewer female patients received post-secondary education and unemployment rates for patients 20 to 24 years of age were higher.

CONCLUSION

Our results indicate that JRA is a disease that often extends into adulthood. Compared to previous decades, functional outcome has improved; however, the estimated rate of arthroplasty remains very high. Patients with JRA may have difficulty entering the workforce.

Long-term outcomes and predictors of outcomes for patients with juvenile idiopathic arthritis

Prediction of the long-term outcome for patients with juvenile idiopathic arthritis requires assessment of disability, psychosocial and socioeconomic function. Measures for the first have evolved from Steinbrocker functional classifications to validated self-administered questionnaires. The proportion of patients with severe disability has decreased during the past three decades but significant numbers of patients enter adulthood with some disability detected with the newer measures. Despite careful study, few early predictors of a poor outcome have been identified. The most consistent are early age at onset, persistent fever and thrombocytosis in patients with systemic juvenile idiopathic arthritis. Reports of psychosocial and socioeconomic outcomes are controversial and further analyses of these spheres are required. An increased risk of osteoporosis and osteopenia has been reported in adults with juvenile idiopathic arthritis. The most significant problem faced by patients during adulthood is persistent disease activity as disability, radiographic damage and the risk of osteoporosis all increase with increasing duration of disease.

Comparative epidemiology of the rheumatic diseases in children

Publications from different countries collectively confirm distinctions in the occurrence of pediatric rheumatic diseases among different populations. In part, this heterogeneity is due to differences in the distribution of human leukocyte antigen alleles. The epidemiology of the various forms of pediatric chronic arthritis has been studied most extensively. However, it is clear that these are complex conditions involving multiple genes as well as environmental and probably developmental factors. Other publications during the past year have updated the epidemiology of Kawasaki disease, Behcet disease, and acute rheumatic fever.

Primary antiphospholipid syndrome with moyamoya-like vascular changes

We describe a young girl with antiphospholipid syndrome (APS) and moyamoya-like cerebrovascular changes which reversed after anticoagulation. Although there was a risk of hemorrhage from collateral vessels, we speculate that this treatment may have prevented progression of the vascular abnormalities, while resolution of the thrombus resulted in improved cerebrovascular circulation.

HLA associations of seropositive rheumatoid arthritis in a Cree and Ojibway population

OBJECTIVE

To determine the HLA associations of seropositive rheumatoid arthritis (RA) in a Cree and Ojibway population; to determine whether specific alleles distinguish juvenile or adult onset.

METHODS

HLA-A, B, C, and DRB1 alleles were analyzed in 23 Ojibway and Cree patients with RA seen in a single tertiary care center. Comparisons were made with published results of controls and with results of 18 patients with rheumatoid factor (RF) positive polyarticular juvenile rheumatoid arthritis (JRA) from the same population.

RESULTS

Comparisons among patients with RA, patients with RF positive polyarticular JRA, and controls showed increased frequencies of the RA shared epitope in patients with RA and of DRB1*0901 in patients with seropositive polyarticular JRA, while the frequency of DRB1*08 alleles was decreased in patients with RF positive polyarticular JRA.

CONCLUSION

In this population, DRB1*0901 may promote while DRB1*08 alleles may protect against a juvenile onset of RA specifically. In contrast, the RA shared epitope may have a greater effect on the risk of adult onset seropositive RA. Due to the small patient numbers, these results require confirmation.

Juvenile rheumatoid arthritis in a Canadian First Nations (aboriginal) population: onset subtypes and HLA associations

OBJECTIVE

To determine onset subtypes and HLA associations of juvenile rheumatoid arthritis (JRA) in a First Nations (aboriginal) population; to determine whether population frequencies of HLA antigens may explain the distribution of subtypes of JRA in this population.

METHODS

All patients were children from Manitoba and Northwestern Ontario seen in a single pediatric rheumatology clinic between 1975 and 1996. Patients were identified from a clinic registry. Controls were adults of Algonkian Cree and Ojibway heritage. Class I and II major histocompatibility (HLA) typing was performed for First Nations patients and controls.

RESULTS

There were a total of 74 First Nations patients with JRA. The relative frequency of rheumatoid factor (RF) positive polyarticular JRA was higher and that of pauciarticular JRA was lower in First Nations compared with Caucasian patients (42 versus 3% and 22 versus 58%, respectively; p = 0.00000). HLA-DRB1*04 (63%), 08 (43%), and 1402 (25%) were the most common DRB1 antigens among controls. The main subtypes of DRB1*04 were 0404 (33% of controls) and 0407 (23%). HLA typing was performed for 39 First Nations patients; 27 were Cree or Ojibway, 4 were from other tribes, and 8 were part First Nations. Among Cree and Ojibway, 59% of controls and 63% of patients with RF positive polyarticular JRA (n = 16) had HLA-DRB1 antigens bearing the rheumatoid arthritis (RA) shared epitope (OR 1.16, 95% CI: 0.38, 3.48). The OR for polyarticular RF positive JRA in those with DRB1*0802 and 0901 were 0.15, 95% CI: 0.02; and 1.24 and 5.83, 95% CI: 1.58, 28.38, respectively.

CONCLUSION

There was a high frequency of the RA shared epitope represented by both HLA-DRB1*0404 and 1402 in this Algonkian population. This high frequency may explain the high frequency of RF positive polyarticular JRA. DRB1*0802 may be protective, whereas DRB1*0901 may increase the risk for this subtype of JRA.

Epidemiology of juvenile rheumatoid arthritis in Manitoba, Canada, 1975-92: cycles in incidence

OBJECTIVE

To determine the yearly incidence of juvenile rheumatoid arthritis (JRA) and to seek correlations between this and cyclic infections occurring in the province of Manitoba, Canada, during the same period.

METHODS

An estimate of the incidence of JRA in Manitoba was determined from a disease registry of the Pediatric Rheumatology Clinic, Children's Hospital, Winnipeg. The numbers of confirmed Mycoplasma pneumoniae and viral respiratory infections were determined from annual reports of Cadham Provincial Laboratory. Both facilities provide centralized services for the province.

RESULTS

Between 1975 and 1992 the onset of JRA occurred in 261 patients (136 with pauciarticular, 91 polyarticular, and 34 systemic onset). The average annual incidence of JRA for this period was 5.34/100,000. However, a cyclic incidence was apparent with peaks in 1979, 1982, 1986, and 1990-91. Increases in confirmed M. pneumoniae infections were concurrent with peaks in the incidence of JRA. A significant correlation was found between the incidence of JRA and the number of M. pneumoniae infections detected in the province between 1985 and 1992 (R = 0.76, p = 0.044). In contrast, there was no consistent variation in the incidence of seronegative spondyloarthropathies in children (n = 103 patients).

CONCLUSION

These data suggest the need for further study of a possible infectious etiology for JRA.