Children with juvenile arthritis who also have enthesitis have worse quality of life, impaired function, and higher pain intensity according to self-reported outcomes, a large-scale study shows.
Patient-reported outcomes are a fundamental tool to help physicians assess the clinical status of children with rheumatic diseases. However, in many cases these self-reported outcomes are not accurate and often are inconsistent with outcomes measured by physicians.
This is particularly true in children with enthesitis-related arthritis. It has been suggested that this condition is not a juvenile arthritis category with unique characteristics “since some children with psoriatic juvenile arthritis have similar characteristics, such as older age at diagnosis, axial involvement, and enthesitis,” suggesting a “common underlying biology between these two categories,” researchers explained.
Enthesitis is characterized by the inflammation of the sites where tendons and ligaments attach to the bone. It is a feature that characterizes enthesitis-related arthritis (ERA), with children reporting more frequent pain, higher pain intensity, and more impairment of function, compared to children with other types of juvenile arthritis.
Researchers from the Research in Arthritis in Canadian Children emphasizing Outcomes (ReACCh Out) study group explored the potential of patient-reported outcomes to assess the impact of enthesitis in children with juvenile idiopathic arthritis(of unknown origin), irrespective of disease category.
The team evaluated the clinical records of 1,371 children diagnosed with juvenile idiopathic arthritis at 16 Canadian centers from 2005 to 2010.
Upon a median follow-up of approximately three years, 214 children (16%) had developed enthesitis, with about 53% of the cases being already detectable at the beginning of the study. By two years, 204 (93%) had developed enthesitis.
Children with enthesitis were more likely to be boys and older at the onset of juvenile arthritis compared to those without this complication. More than half of these patients (64%) were identified as having enthesitis-related arthritis, while 18% had undifferentiated juvenile arthritis. Of note, as per ILAR criteria (International League of Associations for Rheumatology) it is possible to have ERA without having had enthesitis.
Juvenile arthritis patients with enthesitis had significantly worse overall quality of life than those without enthesitis, as determined by higher scores in the Juvenile Arthritis Quality of life Questionnaire (JAQQ).
The same trend was observed concerning health-related quality of life (HRQoL), which was more negatively affected in patients with enthesitis. HRQoL scores decreased throughout time in a similar pattern in patients with and without enthesitis. Still, those with enthesitis always had worse HRQoL scores.
Patient-reported functional ability and pain showed that juvenile arthritis patients with enthesitis had significantly higher (worse) scores. Additional analyses confirmed that for every additional affected enthesis site, both features became significantly worse.
“Patient-reported outcomes are children and families’ way of telling physicians how they are doing and what matters most to them,” researchers wrote. “The fact that all the patient-reported outcomes were worse in children with enthesitis, however, points to an important trend.”
Because enthesitis can have major impact on patient’s well-being, clinicians should make sure to assess its presence and adequately manage it in every child with juvenile arthritis, the researchers advised.