Measurement Properties of Patient-Reported Outcome Measures for Pruritus: An Updated Systematic Review

This systematic review aims to provide an update on measurement properties of patient-reported outcome measures for pruritus. A Medline literature search was conducted to update the systematic review published in this journal in 2017 and to identify new validation studies published between October 2015 and July 2019. The methodological quality of validation studies was assessed on the basis of the COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) checklist, and the measurement properties of patient-reported outcome measures were evaluated. A total of 19 new studies were included and added to the 22 studies identified in the previously published review. Evidence from all the 41 studies evaluating 38 different measures was summarized. Outcome measures were mapped to one of three constructs where possible: pruritus intensity, pruritus severity, pruritus-specific health-related QOL. COSMIN rating revealed mixed results, with deficiencies in the methodological quality of many studies across all constructs. The most appropriate pruritus severity measure was the Itch Severity Scale. ItchyQoL and the disease-specific Uremic Pruritus in Dialysis Scale achieved the most promising results considering the construct pruritus-specific health-related QOL. For pruritus intensity, nine measures performed similarly well.