Infants' Dermatitis Quality of Life Index: a decade of experience of validation and clinical application

The Infants' Dermatitis Quality of Life Index (IDQoL) is a questionnaire completed by parents to assess the impact of atopic dermatitis on the quality of life of infants aged 0-3 years. The aim was to review all clinical and psychometric data on the use of the IDQoL from its inception in 2001 until November 2012, to serve as a single reference source. A literature search was carried out using Medline, PubMed, EBSCOhost, Science Direct and Google Scholar. Articles and abstracts that described the clinical use of the IDQoL and those that investigated its psychometric properties were included. Articles not in English were excluded. Fifty-one publications were identified, of which 46 fulfilled the inclusion criteria. IDQoL data relating to psychometric, descriptive and clinical practice research, drug trials and therapeutic interventions were extracted. The IDQoL has been translated into 21 languages and used in 18 countries, including two multinational studies. Thirty-one studies demonstrated its psychometric properties, such as test-retest reliability, internal consistency, validity, responsiveness to change and interpretability. No studies investigated dimensionality, carried out factor analysis or described the minimal clinically important difference of the tool. Eight studies used the IDQoL to assess the effectiveness of therapeutic interventions such as education programmes, consultations and wet-wrap therapy, while seven studies described the use of IDQoL in topical interventions. When deciding whether to use the IDQoL, researchers and clinicians should consider the validation data, the relevant comparative clinical data available and the potential burden on the respondents.