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

Abstract

BACKGROUND\nChronic pruritus (CP) significantly affects patients health-related quality of life (HRQoL). Very few self-reported HRQoL questionnaires exploring CP were developed according to international guidelines thus limiting their use in pre-authorization trials.\n\n\nOBJECTIVES\nTo develop a self-reported HRQoL questionnaire in patients with CP due to psoriasis, atopic dermatitis, seborrheic dermatitis of the scalp or idiopathic dermatitis; to explore its preliminary psychometric properties.\n\n\nMETHODS\nThe study was performed in France. A conceptual framework was developed based on a structured literature review and experts insight, and was improved with 3 focus groups involving 19 participants. A 50-items 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 (inter-item, item-total score and item-dimension score) were measured. The number of items was reduced through experts consensus.\n\n\nRESULTS\nIn the 39-item version, three main dimensions were identified; Cronbach s alpha=0.94; all correlation coefficients were >0.34. Thirteen items were deleted due to poor quality and six items were deleted by the team, generating a 20-item version. Its factorial structure was best reflected with a two-dimension solution: (i) social and emotional repercussions; (ii) relation to others, fear of judgement.\n\n\nCONCLUSION\nThe Chronic Itch Burden Scale patient-reported questionnaire explores broad aspects of HRQoL relevant for patients with various skin diseases. Its good cross-sectional validity makes it useful for trials and practitioners.