Construct validity and responsiveness of the Child Health Questionnaire in children with acute asthma.

OBJECTIVE: To examine the validity and responsiveness of the Child Health Questionnaire (CHQ-PF28) in the context of acute exacerbation of asthma in children.

DESIGN AND METHODS: This was a prospective cohort study of children age 5 years and older treated for acute asthma at two urban pediatric emergency departments (EDs). At 14 days after the visit, all patients were contacted by telephone and the CHQ-PF28 (modified to have a 2-week recall period) was administered. Poor 14-day outcome was defined as one or more of the following: child or parent missed at least 5 days of school/day care/work; child still having asthma symptoms above baseline at 14 days; or unscheduled care within 7 days after the ED visit.

RESULTS: A total of 732 subjects (median age, 9 years) were enrolled; 622 (85%) had successful follow-up at day 14. At the 14-day follow-up, 254 (43%) were classified as having a poor outcome. The mean physical subscale score of the CHQ-PF28 was 48.2 among those with a good outcome, vs 35.9 among the poor outcome group (difference = 12.3; 95% confidence interval, 10.2 to 14.3). For the psychosocial subscale the average difference between groups was 6.9 (95% confidence interval, 5.1 to 8.7). Among the 146 patients at one site who also had a CHQ score obtained at the initial visit, there was a significant improvement in mean physical subscale score among those with good, but not poor, outcome. However, the relative responsiveness was moderate, with an effect size of only 0.37.

CONCLUSIONS: Both the physical and psychosocial subscales of the CHQ-PF28 administered 14 days after an ED visit for acute exacerbation of asthma are correlated with poor short-term functional outcome, but scores are only moderately responsive to acute changes in functional status.