Cross-cultural selection and validation of instruments to assess patient-reported outcomes in children and adolescents with achondroplasia

Achondroplasia, as the most common form of disproportionate short stature, potentially impacts the health-related quality of life (HRQOL) and functioning of people with this condition. Because there are no psychometrically validated patient-reported outcome (PRO) condition-specific instruments for achondroplasia, this study selected and tested available generic, disease-specific and under development questionnaires for possible use in multinational clinical research.

A three-step approach was applied. First, a literature review and clinician/expert opinions were used to select relevant PRO questionnaires. Second, focus group discussions, including a group cognitive debriefing for piloting of the questionnaires with children/adolescents with achondroplasia and their parents, were performed in Spain and Germany. Third, a field-test study was conducted to test the psychometric properties of these instruments.

Six questionnaires were identified as potentially relevant in children with achondroplasia. In each country, five focus groups including a cognitive debriefing were conducted, and the results narrowed the possibilities to three instruments as most appropriate to assess HRQOL (the generic PedsQL, the height-specific QoLISSY, and the achondroplasia-specific APLES). Results of the field study indicate the QoLISSY and the PedsQL questionnaires to be most appropriate for use in clinical research at this time.

This selection study is a step forward in assessing the impact of achondroplasia on HRQOL. Of the instruments examined, the QoLISSY and the PedsQL both capture items relevant to children with achondroplasia and have met the psychometric validation criteria needed for use in research. The APLES instrument is a promising tool that should be revisited upon psychometric validation.