An ICF-CY-based approach to assessing self- and observer-reported functioning in young persons with achondroplasia - development of the pilot version of the Achondroplasia Personal Life Experience Scale (APLES).

Purpose: Achondroplasia is the most common disproportionate short stature which impacts patients' well-being. Little is known about the burden of disease in terms of functioning of patients and few disease-specific patient-reported outcome (PRO) measures exist. To understand the consequences of achondroplasia, the objective of the study was to develop an achondroplasia-specific PRO tool.

Method: Focus group discussions including 34 German patients (age 8-18 years) and 21 parents were conducted and qualitatively analyzed. To identify relevant concepts, statements were coded according to the International Classification of Functioning, Disability and Health: Children & Youth version (ICF-CY). Upon condensation, relevant statements were reformulated as items.

Results: 1950 statements related to 125 ICF-CY categories were identified. After condensation and prioritization, 59 items were retained. These were generated based on the ICF-CY domains environmental factors (27 items), activities and participation (18 items), body functions (9 items), and body structures (5 items).

Conclusions: A new instrument, the Achondroplasia Personal Life Experience Scale (APLES) to assess burden of disease and functioning from the patients perspective of children and adolescents with achondroplasia has been developed in its pilot version based on the classification of the ICF-CY. Psychometric performance of the APLES is currently being examined. Implications for Rehabilitation Using the ICF-CY within the development of a disease-specific instrument to assess burden of disease and functioning provides guidance for clinicians and researchers in the selection of appropriate instruments complying with ICF categories. Qualitative research based on focus group interviews is an effective method to elicit experiences, beliefs, points of view, understandings, perceptions, impressions, needs and concerns as well as attitudes from the perspective of the individuals on a specific topic such as functioning. Direct assessment of the patient perspective is necessary to thoroughly understand a patient's experience of disease and treatment, the impact on their functioning and relevant health-care needs. Including the perspective of the patient and its family is an important component in the provision of health-care services. Patient-reported outcomes are not only important for the development of interventions and the use in clinical trials but can also be used in medical decision-making processes.