[Development of parent-rated quality of life questionnaire for asthmatic children and their parents or caregivers--reliability and factorial validity].

We developed a questionnaire form on quality of life (QOL) designed for data entry by parents or caregivers of asthmatic children, which consisted of five domains: physical, social, family, emotional, and individual growth domains. QOL scores were determined according to the five-point scale by which one point was given for maximal impairment and five points for no impairment. The form included 23 questions for children under the age of four and 31 questions for children over the age of four. This study examined reproducibility, reliability, and factorial validity of the form. The numbers of asthmatic children, whose symptoms of asthma attacks had been stable for the 2 weeks before this study, were as follows: eight children under the age of four; and 26 children over the age of four. The intra-class correlation coefficients for these two categories of children were 0.879 and 0.793, respectively; therefore, reproducibility was shown. The values of Cronbach's alfa for the total scores of QOL were 0.6329 to 0.8829 in 102 asthmatic children, 40 healthy children, and 12 non-asthmatic children, e.g., children affected by cold. Therefore, internal consistency was shown. The rank-orders of the replies to the questions associated with the physical, social, family, and emotional domains other than the individual growth domain decreased significantly (p < 0.05) in asthmatic children as compared with healthy or non-asthmatic children. Factor analysis confirmed the five established domains and each facets therein at the cumulative variance of 60% or higher. In conclusion, this questionnaire form on QOL of asthmatic children was considered to have reproducibility, constitutional reliability, and factorial validity, to be applicable at the time of medication, and to be useful in investigating approaches for the management of bronchial asthma and the targeting of treatment.