Growth patterns in early juvenile idiopathic arthritis: Results from the Childhood Arthritis Prospective Study (CAPS)

OBJECTIVES

To investigate early vertical growth patterns and factors associated with poor growth in a modern inception cohort of UK children with juvenile idiopathic arthritis (JIA) using data from the Childhood Arthritis Prospective Study (CAPS).

METHODS

A study period of 3 years was chosen. Children included in this analysis had a physician diagnosis of JIA and had height measurements available at both baseline and at 3-years of follow-up. Height is presented as z-scores calculated using World Health Organisation growth standards for age and gender. Growth over the 3-year period was assessed using change in z-score and height velocity. Univariable and multivariable linear regressions were used to identify factors associated with height z-score at baseline and change of height z-score at 3 years.

RESULTS

568 patients were included; 65% female, median baseline age 7.4 years [interquartile range (IQR) 3.6, 11.2], median symptom duration at presentation 5.5 months [IQR 3.1, 11.6]. Height z-score decreased significantly from baseline to 3 years (p ≤ 0.0001); baseline median height z-score was -0.02 (IQR -0.71, 0.61), decreasing to -0.47 (IQR -1.12, 0.24) at 3 years. Growth restriction, defined as change of height z-score ≤-0.5, was observed in 39% of patients. At 3 years, higher baseline height z-score was the strongest predictor for a negative change in height z-score [-0.3 per unit of baseline height z-score (95% CI: -0.36, -0.24), p < 0.0001].

CONCLUSIONS

Although overall height at 3 years after initial presentation to rheumatology is within the population norm, as a cohort, children with JIA experience a reduction of growth in height over the first 3 years of disease. Late presentation to paediatric rheumatology services is associated with lower height at presentation. However, patients with the lowest height z scores at presentation were also the most likely to see an improvement at 3 years. The impact of JIA on growth patterns is important to children and families and this study provides useful new data to support informed clinical care.

Treatment prescribing patterns in patients with juvenile idiopathic arthritis (JIA): Analysis from the UK Childhood Arthritis Prospective Study (CAPS)

OBJECTIVE

Initial treatment of juvenile idiopathic arthritis (JIA) is largely based on the extent of joint involvement, disease severity and ILAR category. The licensing of biologic therapies for JIA has expanded treatment options. The aims of the study are (1) to describe treatment prescribing patterns in JIA over the first 3 years following first presentation to paediatric rheumatology and (2) to determine whether patterns of treatment have changed as biologics have become more widely available.

METHODS

Children with at least 3 years of follow-up within the Childhood Arthritis Prospective Study (CAPS) were included. For analysis, children were placed into one of five groups according to their initial presentation to paediatric rheumatology: oligoarthritis (oJIA), polyarthritis (pJIA), systemic (sJIA), enthesitis-related arthritis (ERA) and psoriatic arthritis (PsA). Treatment patterns over 3 years were described.

RESULTS

Of 1051 children, 58% received synthetic disease-modifying anti-rheumatic drugs (sDMARD) and 20% received biologics over the 3 years. Use of sDMARDs and biologics was higher in more severe disease presentations (sJIA and pJIA); however, 35% and 10% who presented with oJIA were also treated with sDMARDs and biologics, respectively. The number of children receiving sDMARD after 2006 was higher (p = 0.02); however, there was no difference in biologic prescribing before and after 2006 (p = 0.4).

CONCLUSIONS

A high proportion of children presenting with JIA received sDMARDs plus/minus biologics during 3 years of follow-up. This was most common for patients with severe JIA but was also prescribed for patients with oligoarticular disease, despite the lack of evidence for effectiveness in this category.

Trends in paediatric rheumatology referral times and disease activity indices over a ten-year period among children and young people with Juvenile Idiopathic Arthritis: results from the childhood arthritis prospective Study

Objectives. The medical management of JIA has advanced significantly over the past 10 years. It is not known whether these changes have impacted on outcomes. The aim of this analysis was to identify and describe trends in referral times, treatment times and 1-year outcomes over a 10-year period among children with JIA enrolled in the Childhood Arthritis Prospective Study.

Methods. The Childhood Arthritis Prospective Study is a prospective inception cohort of children with new-onset inflammatory arthritis. Analysis included all children recruited in 2001–11 with at least 1 year of follow-up, divided into four groups by year of diagnosis. Median referral time, baseline disease pattern (oligoarticular, polyarticular or systemic onset) and time to first definitive treatment were compared between groups. Where possible, clinical juvenile arthritis disease activity score (cJADAS) cut-offs were applied at 1 year.

Results. One thousand and sixty-six children were included in the analysis. The median time from symptom onset and referral to first paediatric rheumatology appointment (22.7–24.7 and 3.4–4.7 weeks, respectively) did not vary significantly (∼20% seen within 10 weeks of onset and ∼50% within 4 weeks of referral). For oligoarticular and polyarticular disease, 33.8–47 and 25.4–34.9%, respectively, achieved inactive disease by 1 year, with ∼30% in high disease activity at 1 year. A positive trend towards earlier definitive treatment reached significance in oligoarticular and polyarticular pattern disease.

Conclusion. Children with new-onset JIA have a persistent delay in access to paediatric rheumatology care, with one-third in high disease activity at 1 year and no significant improvement over the past 10 years. Contributing factors may include service pressures and poor awareness. Further research is necessary to gain a better understanding and improve important clinical outcomes.

Validity of a three-variable Juvenile Arthritis Disease Activity Score in children with new-onset juvenile idiopathic arthritis

OBJECTIVES

To investigate the validity and feasibility of the Juvenile Arthritis Disease Activity Score (JADAS) in the routine clinical setting for all juvenile idiopathic arthritis (JIA) disease categories and explore whether exclusion of the erythrocyte sedimentation rate (ESR) from JADAS (the 'JADAS3') influences correlation with single markers of disease activity.

METHODS

JADAS-71, JADAS-27 and JADAS-10 were determined at baseline for an inception cohort of children with JIA in the Childhood Arthritis Prospective Study. JADAS3-71, JADAS3-27 and JADAS3-10 were determined using an identical formula but with exclusion of ESR. Correlation of JADAS with JADAS3 and single measures of disease activity/severity were determined by category.

RESULTS

Of 956 eligible children, sufficient data were available to calculate JADAS-71, JADAS-27 and JADAS-10 at baseline in 352 (37%) and JADAS3 in 551 (58%). The median (IQR) JADAS-71, JADAS-27 and JADAS-10 for all 352 children was 11 (5.9-18), 10.4 (5.7-17) and 11 (5.9-17.3), respectively. Median JADAS and JADAS3 varied significantly with the category (Kruskal-Wallis p=0.0001), with the highest values in children with polyarticular disease patterns. Correlation of JADAS and JADAS3 across all categories was excellent. Correlation of JADAS71 with single markers of disease activity/severity was good to moderate, with some variation across the categories. With the exception of ESR, correlation of JADAS3-71 was similar to correlation of JADAS-71 with the same indices.

CONCLUSIONS

This study is the first to apply JADAS to all categories of JIA in a routine clinical setting in the UK, adding further information about the feasibility and construct validity of JADAS. For the majority of categories, clinical applicability would be improved by exclusion of the ESR.