Papers of the Week

Current patient-reported outcome measures for itch are limited and may not capture its full impact on health-related quality of life (HRQOL). We sought to develop, calibrate and validate banks of questions assessing the HRQOL impact of itch as part of Patient-Reported Outcomes Measurement Information System® (PROMIS®). A systematic process of literature review, content-expert review, qualitative research, testing in a sample of 600 adults, classical test theory methods, and item response theory (IRT) analyses were applied. Exploratory and confirmatory factor analyses were followed by item response theory (IRT) model and item fit analyses. Four itch-related item banks were developed: (1) general concerns, (2) mood and sleep, (3) clothing and physical activity, and (4) scratching behavior. IRT and expert content review narrowed the item banks to 25, 18, 15 and 5 items, respectively. Validity of the item banks was supported by good convergent and discriminant validity with itch intensity, internal consistency and no significant floor or ceiling effects. In conclusion, the PROMIS Itch Questionnaire (PIQ) banks have excellent measurement properties and efficiently and comprehensively assess the burden of itch.