Letter on "Validation of the Brief International Classification of Functioning, Disability, and Health (ICF) Core Set for Hand Conditions".

STUDY DESIGN Cross-sectional multi-centre study. INTRODUCTION The ICF Core Sets for Hand Conditions (HC) have been developed to describe functioning of patients with HC. PURPOSE OF THE STUDY To study the content validity of the Brief ICF Core Set for HC. METHODS Patients with HC were interviewed using the Comprehensive ICF Core Set for HC. ICF categories that best explained variation in patients' general health were identified using multiple regression methods. RESULTS Overall, 12 of the 23 ICF categories of the Brief ICF Core Set could be validated. Our analyzes further revealed that the categories "b134 Sleep functions", "s830 Structure of nails", "e225 Climate" as well as categories referring to "e4 Attitudes" also deserve consideration when assessing functioning in patients with HC. CONCLUSIONS Clinicians are encouraged to complement the Brief ICF Core Set for HC by adding sleep functions, structure of nails, climate and attitudes, especially when following patients over time. LEVEL OF EVIDENCE Level 3.