The German version of the chronic urticaria quality‐of‐life questionnaire: factor analysis, validation, and initial clinical findings

Abstract

Chronic urticaria (CU) is a common skin disorder that causes a substantial burden on patients' quality-of-life (QoL). The aim of this work was to generate and validate a German version of the Chronic Urticaria Quality of Life Questionnaire (CU-Q(2)oL) and to provide reference assessments of QoL. The Italian CU-Q(2)oL was translated into German and administered to 157 CU patients. They also completed two well-established general dermatology QoL questionnaires, the Dermatology Life Quality Index (DLQI) and Skindex-29. Factor analysis was used to identify scales of the German CU-Q(2)oL. Correlation to the DLQI and Skindex-29 was used for validation. Multiple linear regression was used to determine which patient characteristics were associated with which dimensions of QoL. The factor analysis identified six scales of the German CU-Q(2)oL: functioning, sleep, itching/embarrassment, mental status, swelling/eating, and limits looks, which accounted for 70% of the data variance. Five of these six scales showed good internal consistency, and another five demonstrated convergent validity. On a percentile scale, they had these median CU-Q(2)oL scores: 29 functioning, 44 sleep, 50 itching/embarrassment, 50 mental status, 31 swelling/eating, 31 limits looks. Disease severity significantly predicted scores on all scales. Age predicted functioning, sleep, itching/embarrassment, and swelling/eating. Sex predicted itching/embarrassment and limits looks. This study yielded a robust validation of the German version of the CU-Q(2)oL. It confirmed previous studies that CU has a clinically meaningful burden on QoL, especially for sleep and mental health, and that women are more severely affected by pruritus. The German CU-Q(2)oL should be widely adopted in clinical research on the treatment of CU.