Reliability of exercise testing and functional activity questionnaires in children with juvenile arthritis.
OBJECTIVE
To determine the reliability of formal exercise testing and the reliability of functional and activity questionnaires in children with juvenile idiopathic arthritis (JIA).


METHODS
Children with JIA of any subtype ages 8-16 years who were recruited to a randomized trial comparing different exercise therapies participated in 2 preintervention sessions of exercise testing 2-6 weeks apart. Exercise testing included 1) submaximal oxygen uptake (VO(2submax)), 2) peak VO(2) (VO(2peak)), and 3) anaerobic power using modified Wingate tests (W(ant)). Two physical function questionnaires (the Childhood Health Assessment Questionnaire [C-HAQ] and Revised Activity Scale for Kids [ASK]) and 1 daily physical activity questionnaire (the Habitual Activity Estimation Scale [HAES]) were also completed at these times. Test-retest reliability was assessed using type 3, intrarater intraclass correlation coefficient (ICC(3,1)) and Bland and Altman plots were used to determine limits of agreement.


RESULTS
Data were available for 74 patients (58 girls). VO(2submax), VO(2peak), and W(ant) demonstrated high reliability (ICC(3,1) 0.82, 0.91, and 0.94, respectively). C-HAQ and ASK questionnaires also had very high reliability (ICC(3,1) 0.82 and 0.91, respectively). The HAES demonstrated low reliability for total activity score (ICC(3,1) 0.15) and moderate reliability when the number of very active hours was analyzed separately (ICC(3,1) 0.59).


CONCLUSIONS
Results of this investigation suggest that exercise testing and functional questionnaires in children with JIA are consistent and reliable. Reliability of the HAES total score was poor, but moderate when the very active hours subscale score was used.
The Hospital for Sick Children, Toronto, Ontario, Canada.
Samantha
S
Stephens
Davinder
D
Singh-Grewal
Oded
O
Bar-Or
Joseph
J
Beyene
Bonnie
B
Cameron
Claire M A
CM
Leblanc
Rayfel
R
Schneider
Jane
J
Schneiderman-Walker
Hiran
H
Selvadurai
Earl
E
Silverman
Lynn
L
Spiegel
Shirley M L
SM
Tse
Virginia
V
Wright
Brian M
BM
Feldman
D000203:Activities of Daily Living; D000293:Adolescent; D001171:Arthritis, Juvenile / Q000503:physiopathology*; D002648:Child; D004185:Disability Evaluation; D005080:Exercise Test / Q000592:standards / Q000706:statistics & numerical data*; D005260:Female; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care; D010101:Oxygen Consumption / Q000502:physiology; D015203:Reproducibility of Results