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

Purpose: 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.

Methods: A three-step approach was applied.

Piloting and psychometric properties of a patient-reported outcome instrument for young people with achondroplasia based on the International Classification of Functioning Disability and Health: the Achondroplasia Personal Life Experience Scale (APLES).

This study describes the psychometric testing of the Achondroplasia Personal Life Experience Scale (APLES): a new disease- and functioning-specific health-related quality of life instrument for young people with achondroplasia, which was developed based on the International Classification of Functioning-Children and Youth Version. The qualitative analysis of focus group statements from German patients and parents using the International Classification of Functioning-Children and Youth Version yielded 59 items, which after cognitive debriefing were included in a pilot-test. Psychometric performance was cross-culturally examined in a field- and re-test in Germany and Spain.