Parental perception of health-related quality of life in children and adolescents with short stature: literature review and introduction of the parent-reported QoLISSY instrument

BACKGROUND: Health-related quality of life (HrQoL) of the child diagnosed with short stature is an important outcome to be assessed both from the patient as well as from the parental perspective. The objective of this study was to review the literature on parent-reported HrQoL and to subsequently develop and psychometrically test the parent-reported version of the Quality of Life in Short Stature Youth (QoLISSY) instrument for use in clinical and epidemiologic research.

METHODS: A review of the literature on parental assessment of child HrQoL via PUBMED was followed by a psychometric analysis of data collected within the European QoLISSY study, in which 686 eligible parents of short statured children/adolescents (aged 4-18 years) meeting inclusion criteria participated. Patient inclusion criteria were a height below -2 SD, a diagnosis of growth hormone deficiency (GHD) or idiopathic short stature (ISS), and treatment status in terms of receiving or not receiving recombinant human growth hormone therapy. Focus groups eliciting parental HrQoL statements, pilot testing with cognitive debriefing, and a field test in 317 parents with a retest in 148 parents were conducted simultaneously in France, Germany, Spain, Sweden and the UK. The psychometric performance of the parent-reported instrument, developed in parallel to the child/ adolescent self-report version, was assessed using standard tests of reliability and validity.

RESULTS: Literature search failed to identify a cross-culturally developed height specific instrument available for both patient self-report and parental observer report. Analysis of the QoLISSY focus group phase conducted separately in children, adolescents and parents yielded 169 items generated from parent focus groups. A cognitive debriefing exercise followed by a pilot test of preliminary psychometric characteristics resulted in deleting poorly performing items. Field testing of the parent-reported version suggested a three-domain core HrQoL structure with 22 items, additional 44 items assessing three mediator domains and two parent specific domains. The parent report version demonstrated good criterion and construct validity as well as internal consistency and test retest reliability.

CONCLUSIONS: The QoLISSY parent report questionnaire closes a gap in the simultaneous assessment of parent and child perception of HrQoL in an international context. It is based on items generated from the experience of short statured children, adolescents and their parents and is validated for use in five European languages. It is feasible, relevant for this population, psychometrically sound and is easy to administer in research and clinical settings.