Validation of the International Classification of Functioning, Disability and Health Core Set for chronic widespread pain from the perspective of fibromyalgia patients

INTRODUCTION: Functioning is recognized as an important study outcome in chronic widespread pain (CWP). The Comprehensive ICF Core Set for CWP is an application of the International Classification of Functioning, Disability and Health (ICF) with the purpose of representing the typical spectrum of functioning of patients with CWP. The objective of the study was to add evidence to the validation of the Comprehensive ICF Core Set for CWP from the patient perspective. The specific aims were to explore the aspects of functioning and health important to patients with fibromyalgia, and to examine to what extent these aspects are represented by the current version of the Comprehensive ICF Core Set for CWP. METHODS: The sampling of patients followed the maximum variation strategy. Sample size was determined by saturation. The focus groups were digitally recorded and transcribed verbatim. The meaning condensation procedure was used for qualitative data analysis. After qualitative data analysis, the identified concepts were linked to ICF categories. RESULTS: Thirty-three patients participated in six focus groups. Fifty-four ICF categories out of 67 categories of the Comprehensive ICF Core Set for CWP were reported by the patients. Forty-eight additional categories that are not covered in the Comprehensive ICF Core Set for CWP were raised. CONCLUSIONS: Most ICF categories of the existing version of the Comprehensive ICF Core Set for CWP could be confirmed from the patient perspective. However, several categories not included in the Core Set emerged and should be considered for inclusion.