Development of Proxy and Self-report Burn Model System Pediatric Itch Interference Scales: A National Institute on Disability, Independent Living, and Rehabilitation Research Burn Model System Study.

Pruritus is a commonly reported symptom after burn injury. Valid and reliable scales to measure itch in pediatric burn survivors are important for treatment and epidemiological studies. This study sought to develop psychometrically sound, publicly available self- and proxy-report measures of itch for use in pediatric burn survivors suitable for use in research and clinical practice. A panel of burn experts developed a definition of itch interference and a set of parallel self- and proxy-report candidate items that covered important activities affected by itch. Candidate items were evaluated in cognitive interviews with pediatric burn survivors (n = 4) and proxies (n = 2). Items were translated to Spanish and administered in both English and Spanish to a sample (N = 264) of pediatric burn survivors and/or their proxy enrolled in the Burn Model System (BMS) longitudinal database. The mean age of the pediatric sample was 13 years and average time since burn 5 years. The final itch interference measures each included 5 parallel items calibrated using a one-parameter graded response item response theory model, with a mean of 50 representing the average itch interference of the sample. Reliability of the scores is excellent between the mean and two standard deviations above. Initial analyses provide support for validity of the score. Concordance between the self- and proxy-report scores was moderate (ICC = 0.68). The results support the reliability and validity of the itch scale in children and youth with burn injury. The new BMS Pediatric Itch Interference scales are freely and publicly available at https://burndata.washington.edu/itch.