Background/Purpose

Juvenile Idiopathic Arthritis (JIA) is often associated with decreased physical activity (PA). Although improved disease control has opened up the possibilities for JIA-children to participate in dynamic sport activities, various limitations secondary to the disease seem to restrict an adequate integration in sport activities. Accurate, objective measurements of PA and identification of specific factors limiting PA in JIA-children are therefore needed.

This study aimed to: 1. Compare accelerometer-assessed PA in JIA-children with normative data of age- and gender-matched healthy controls. 2. Relate accelerometer-assessed PA to joint status in the lower extremities (LE) in JIA-children regarding active arthritis as well as persistent LOM (contractures) and exceeded range of motion (ROM) (hypermobility).

Methods

In 61 patients with JIA PA was assessed using the hip-worn GT1M Actigraph accelerometer during wakening hours for one week, providing at least 3 separate days each of 8 hours of valid recording accelerometer using 10 second intervals of recording (epochs).

Joint status was valuated using a joint activity count of 71 joints. Also, LE-joints (hips, knees, ankles, toes) were examined for persistent LOM and exceeded ROM (Beighton score-items including alternative items to cover all LE- joints).  Demographic, disease- and pain-related parameters were also obtained.

Results

For each age-group between 10-16 years accelerometer data of the 61 JIA patients were compared with 239±93 normative controls. Values of mean counts per minute (c/min), recorded minutes with moderate and high PA (>1000 c/min) and high PA (>2500 c/min) were significantly lower in patients than in normative controls (p≤0.004), with the more severe JIA-subcategories having the lowest values.

PA of JIA-children was significantly correlated to joint swelling (p=0.004) and LOM of the hips and the ankles, but not the knees; no matter if due to active arthritis or contractures. No significant correlations were found between PA of JIA-children and reported pain (p=0.59) and hypermobility (p=0.58).

Conclusion

Accelerometer-assessed PA-levels of JIA-children were significantly lower than those of normative controls. LOM of hips and ankles, but surprisingly not the knees, were significantly associated with impaired PA. This emphasizes the importance of obtaining full ROM specifically in hips and ankles of JIA-children for the purpose of adequately participating in sport activities.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/role-of-joint-status-in-decreased-accelerometer-assessed-daily-physical-activity-in-juvenile-idiopathic-arthritis/