[Short version of a quality-of-life questionnaire in primary caregivers of children with atopic dermatitis (QPCAD): development and validation of QP9].

QPCAD (Quality of life in Primary Caregivers of children with Atopic Dermatitis) is a questionnaire with 19 items, which was developed to evaluate the QOL of primary caregivers of children with atopic dermatitis (AD). We developed an abbreviated version of QPCAD (QP9) to reduce the burden of respondents and to popularize the evaluation of QOL in clinical practice, and evaluated its reliability, validity, and responsiveness.We applied factor analysis to the data of primary caregivers of AD children at the age of 0 to 6, tried to select the items of QP9. Next, we evaluated the reliability of QP9 based on the data of reliability analysis set of caregivers. We also examined the associations of scores of QP9 with background characteristics and the AD severity index for the validity analysis. In addition, we examined associations of the amount of change of scores with that of the AD severity index for the responsiveness analysis.We selected the items of QP9 consisting of 9 items based on the data of 529 primary caregivers. We confirmed sufficient reliability of the item scores. We found the expected associations between the scores and background characteristics and AD severity. We also found the association between the amount of change of pre- and post-treatment scores and that of the AD severity.QP9 must be a useful questionnaire with sufficient reliability, validity, and responsiveness, as a QOL scale of primary caregivers of AD children.