Validity of the childhood health assessment questionnaire is independent of age in juvenile idiopathic arthritis.
OBJECTIVE
To determine whether the Childhood Health Assessment Questionnaire (CHAQ) is valid for the comparison of different age subgroups and for longitudinal studies in juvenile idiopathic arthritis (JIA).


METHODS
A CHAQ was administered to 306 children with JIA. Rasch analyses were used to compare the difficulty of each of the 30 items of the questionnaire for children of 2 age groups (> or =10 years old and <10 years old).


RESULTS
Independent of the physical disability level assessed by the Rasch model, 8 of the 30 items (27%) of the CHAQ were rated significantly different in the 2 age groups. Despite this age-related variation in item difficulty, the impact on the CHAQ disability index using its original scoring system remained low (about 0.25 points on a scale of 0-3).


CONCLUSIONS
The difficulty of 8 of 30 items of the CHAQ depends on the respondent's age. Nevertheless, the design of the CHAQ and its scoring system remove most of the expected physical development bias.
Pouchot
Jacques
J
Hôpital Louis Mourier, Colombes, France. jacques.pouchot@lmr.ap-hop-paris.fr
Ecosse
Emmanuel
E
Coste
Joël
J
Guillemin
Francis
F
D000293:Adolescent; D000367:Age Factors; D001171:Arthritis, Juvenile / Q000175:diagnosis* / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires / Q000592:standards*