Development and preliminary validation of the patient-reported Chronic Itch Burden Scale assessing health-related quality of life in chronic pruritus

Background Chronic pruritus (CP) significantly affects patients' health-related quality of life (HRQoL). Very few self-reported HRQoL questionnaires exploring CP have been developed according to international guidelines, thus limiting their use in preauthorization trials. Objectives To develop a self-reported HRQoL questionnaire in patients with CP owing to psoriasis, atopic dermatitis, seborrhoeic dermatitis of the scalp or idiopathic dermatitis, and to explore the preliminary psychometric properties of the questionnaire. Methods The study was performed in France. A conceptual framework was developed based on a structured literature review and expert insight, and was improved using three focus groups involving 19 participants. A 50-item questionnaire was created and tested with 21 participants using cognitive debriefings; 11 items were removed. A cross-sectional study including 251 participants was performed to explore the preliminary psychometric properties of the 39-item questionnaire. Dimensionality was explored using principal component analysis. Cronbach's alpha and correlation coefficients (interitem, item-total score and item-dimension score) were measured. The number of items was reduced through expert consensus. Results In the 39-item version, three main dimensions were identified (Cronbach's alpha = 0 center dot 94) and all correlation coefficients were > 0 center dot 34. Upon review, 13 items were deleted owing to poor quality and six items were deleted by the team, generating a 20-item version. The questionnaire's factorial structure was best reflected with a two-dimension solution, i.e. (i) social and emotional repercussions and (ii) relation to others, fear of judgement. Conclusions The Chronic Itch Burden Scale patient-reported questionnaire explores broad aspects of HRQoL that are relevant for patients with various skin diseases. Its good cross-sectional validity makes it useful for trials and practitioners.

Automated summary

The study developed a conceptual framework for a self-reported HRQoL questionnaire for patients with Chronic Pruritus, and tested a 50-item questionnaire with 21 participants, resulting in a 39-item version. Through a cross-sectional study with 251 participants, a 20-item version with three main dimensions was identified, and a two-dimension solution was determined for the questionnaire's factorial structure, making it useful for trials and practitioners.