BACKGROUND: The aim of this study was to validate the English version of the Itch Cognition Questionnaire in a sample of patients with chronic itch due to psoriasis or atopic dermatitis. An English-language version of an instrument assessing itch-related cognitions is needed since cognitions can contribute to a worsening of itch, and chronic itch is prevalent in English-speaking counties and internationally.
METHODS: The German Itch Cognitions Questionnaire was translated into English, and cognitive interviewing was conducted to finalize item wording. Internal and test-retest reliability, item discrimination, responsiveness to change, and construct, convergent, and discriminant validity were assessed in a national sample of 137 individuals with chronic itch due to atopic dermatitis or psoriasis recruited online.
RESULTS: Internal reliability was high with Cronbach’s alphas of 0.93 for the Catastrophizing subscale and 0.88–0.90 for Coping. The Pearson’s correlation assessing 1-month test-retest reliability for the Catastrophizing subscale was r = 0.62 and for the Coping subscale was r = 0.61. The corrected item-total correlation revealed that items were relatively consistent with the scores for the subscales (with correlations ranging from 0.58 to 0.79), indicating very good item discrimination. Results of factor analysis, convergent and discriminant, and responsiveness to change analyses provided evidence for validity.
CONCLUSIONS: This study showed good psychometric characteristics of the English version of the Itch Cognitions Questionnaire. We suggest that future studies investigate the use of the measure in clinical practice to assist with treatment planning and outcome assessment related to itch as well as address study limitations such as sampling and replication.
Digital Object Identifier (DOI)
Funding sources included Pfizer WI206759, NIH P30CA006927, and NIH P30CA072720. Anke Ehlers is funded by the Wellcome Trust 200796.
The data files are made available under the Creative Commons Attribution 4.0 International license and are available as the zip file listed at the end of this record.
Description of the data files is as follows:
Background: Many patients with chronic itch and atopic dermatitis (AD) or psoriasis do not receive/use available medical and psychosocial treatments properly due to system, provider, and/or patient factors. Objective: An educational website (ITCH-RELIEF4Me) to improve itch-related quality of life (QoL) for adults with AD or psoriasis and chronic itch was developed and assessed. Psychometric characteristics of the English version Itch Cognitions Questionnaire and two new measures of scratch as well as sleep-related scratch and itch were evaluated. Methods: Single-arm pre- and post-test design with one-month follow up (N = 137 at baseline).
Heckman, Carolyn J.; Schut, Christina; Riley, Mary; Ehlers, Anke; Valdes-Rodriguez, Rodrigo; Kupfer, Jörg; Gieler, Uwe; and Stapleton, Jerod L., "Development and Psychometrics of the English Version of the Itch Cognitions Questionnaire" (2020). Health, Behavior & Society Faculty Publications. 27.