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Exploring the ceiling effect of the revised Childhood Health Assessment Questionnaire in a European patient sample
Pediatric Rheumatologyvolume 6, Article number: P102 (2008)
The original version of the Childhood Health Assessment Questionnaire (CHAQ30orig) suffers from a ceiling effect and hence has reduced clinical validity . The effect of adding eight more demanding items and a new continuous response option (CATII) was tested.
Twenty-four children with JIA  were recruited from eight centres across Europe. Demographic, clinical, and CHAQ data were obtained. Five different score calculations were applied: the original method (CHAQ30orig), and the mean item scores for the 30 and 38-question versions with two categorical response options (Chaq30item CAT I and II and Chaq38item CAT I and II).
Descriptive statistics were calculated and CHAQ-data were tested for normality. A ceiling effect was defined by 15% or more patients scoring the best possible score.
(preliminary, based on 30% of total data).
A ceiling effect was observed in CHAQ30orig and CHAQ30item (20.8% for both). The median scores, KS-statistics, p-values, and interquartile range (IQR) are presented in table 1.
The CHAQ38 with CATII scoring showed best overall distribution characteristics: no ceiling effect, more normally distribution, and the second largest IQR. (In September 2008 final results are presented).
Lam C, Young N, Marwaha J, Mc Limont M, Feldman BM: Revised Versions of the Childhood Health Assessment Questionnaire (CHAQ) Are More Sensitive and Suffer Less From a Ceiling Effect. Arthritis & Rheumatism (Arthritis Care & Research). 2004, 51: 881-889. 10.1002/art.20820.
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