Musculoskeletal pain and its effect on daily activity and behaviour in Icelandic children and youths with juvenile idiopathic arthritis: a cross-sectional case-control study

BACKGROUND: Juvenile idiopathic arthritis is characterised by recurring episodes of acute inflammation, with joint swelling in one or more joints, often accompanied by pain. These episodes can now be controlled better than in the past because of a new category of medications. However, despite more stable disease activity, pain may continue to cause problems in the children with juvenile idiopathic arthritis and can reduce their performance of routine physical activities and participation in social or school activities. AIM: To evaluate the prevalence of pain, pain intensity, pain behaviour, and pain interference in Icelandic children with juvenile idiopathic arthritis compared with healthy peers. METHODS: A cross-sectional, case-control study including 8-18 years old children; 28 with juvenile idiopathic arthritis and 36 in a control group. The children answered questions on pain experienced during the last 7 days, painful areas of the body and pain frequency. They completed short form versions of the Patient-Reported Outcome Measurement Information System (PROMIS) questionnaires on pain intensity, pain behaviour, and pain interference. RESULTS: Significantly more children with juvenile idiopathic arthritis had pain compared with the control group (p = 0.02). Children with JIA also had a greater number of painful body areas (p = 0.03), more pain intensity (p = 0.009), and showed more pain behaviour (p = 0.006), and pain interference (p = 0.002). Children with juvenile idiopathic arthritis who had pain, experienced more pain interference (p = 0.023) than their peers who had pain. However, the groups did not differ in terms of pain intensity (p = 0.102) and pain behaviour (p = 0.058). CONCLUSION: The research results indicate that pain experience was different between children with juvenile idiopathic arthritis and the control group. The results suggest that further research of the role of pain management on functional outcomes in children with juvenile idiopathic arthritis is needed.