Validation of a specific health-related quality of life instrument in a large cohort of patients with psoriasis: the QualiPso Questionnaire.
The aim of this study was to develop and validate a standardized tool designed to assess health-related quality of life (HRQoL) in a large cohort of French patients with psoriasis, the QualiPso Questionnaire. A draft questionnaire was developed based on a literature review, followed by one-to-one interviews of 50 patients with psoriasis conducted by trained psychologists. The interview transcripts were analysed, after which 56 items were retained and validated in a cohort of 569 patients. Four QualiPso subscales were derived from factor analysis. The first factor encompasses disturbances of social life, a key factor in HRQoL among psoriasis patients (Cronbach's alpha coefficient: α=0.948). The second factor assesses the impact of psoriasis on mental health (α=0.932). The third factor reflects concerns related to treatment outcomes (α=0.873), and the fourth factor is related to skin symptoms (α=0.772). The subscales are related but distinct, accounting for 60% of the common variance. In conclusion, the QualiPso questionnaire provides a reliable and valid measure of a patient's psychosocial well-being in relation to psoriasis. It also measures the impact of concerns related to treatment outcomes and skin symptoms, which have not been addressed previously by HRQoL research on psoriasis.