To demonstrate that the Spanish (Castillian) version of the Childhood Health Assessment Questionnaire (cHAQ-S) is a valid and reliable instrument for measuring the health status of children with juvenile chronic (or rheumatoid) arthritis (JCA) and is sensitive to change.
A conceptual translation of the original questionnaire into Spanish and two back-translations were performed. The cHAQ-S was completed by the parents of young children (aged 1 to 19 years) affected by JCA, and additionally by those children aged over 9. A second cHAQ-S was administered at least 15 months after the first one.
The cHAQ-S was administered to 79 patients of patients affected by JCA. The test-retest reliability was evaluated among 16 patients, and no significant differences between the first and second administration were found (0.88 versus 0.84; p > 0.6; intraclass correlation coefficient R = 0.94). The Cronbach's alpha coefficient was 0.948, indicating an excellent internal reliability with a mean correlation between the different components of the questionnaire varying from 0.3557 to 0.7831. For the between-observer reliability, an intraclass correlation coefficient of 0.96 was obtained. Correlations between DI (Disability Index) and several measures of disease activity were all statistically significant (Spearman's R ranged from 0.42 to 0.87; p < 0.005). Patients who improved showed similar improvement in the DI (p = 0.015), while patients who worsened showed a worsening of the DI (p = 0.1) and patients whose condition was stable showed no change in DI (p = 0.6).
The cHAQ-S is a feasible, reliable and valid instrument for the determination of the health status of Spanish children suffering from JCA. It is also sensitive to changes in the child's health status.