German version of ItchyQoL: validation and initial clinical findings

Pruritus is a major symptom of numerous skin and systemic diseases and causes a substantial burden on patients' quality of life (QoL). We report here the validation of the German version (GerItchyQoL) of the first pruritus-specific QoL instrument ItchyQoL. GerItchyQoL was created from the original version following standard protocols. It was completed by 308 patients with chronic pruritus of different origin and tested for validity, reliability and responsiveness. Factor analysis of Ger-ItchyQoL revealed the 4 domains symptoms, functioning, feelings, and self-perception. Reliability was demonstrated by good internal consistency of all domains. We confirmed convergent validity by comparing the instrument with itch severity, as measured with a visual analogue scale (VAS 0-10), and with the Short-Form-12 (SF-12), a widely used generic health-related QoL instrument. Concurrent validity was shown by the ability to discriminate between patient groups of different itch severity. Changes in GerItchyQoL scores correlated with changes in itch severity (VAS), suggesting responsiveness of the German tool. This study provides preliminary evidence of validity, reliability and responsiveness of GerItchyQoL and also shows a high impact of chronic pruritus on QoL. Further translations of ItchyQoL into additional languages will enable large-scale international, multilingual trials.