How to use the Harmonising Outcome Measures for Eczema Core Outcome Set for atopic dermatitis trials: a users' guide

Background The Harmonising Outcome Measures for Eczema (HOME) initiative has agreed upon the Core Outcome Set (COS) for use in atopic dermatitis (AD) clinical trials, but additional guidance is needed to maximize its uptake.Objectives To provide answers to some of the commonly asked questions about using the HOME COS; to provide data to help with the interpretation of trial results; and to support sample size calculations for future trials.Methods and results We provide practical guidance on the use of the HOME COS for investigators planning clinical trials in patients with AD. It answers some of the common questions about using the HOME COS, how to access the outcome measurement instruments, what training/resources are needed to use them appropriately and clarifies when the COS is applicable. We also provide exemplar data to inform sample size calculations for eczema trials and encourage standardized data collection and reporting of the COS.Conclusions By encouraging adoption of the COS and facilitating consistent reporting of outcome data, it is hoped that the results of eczema trials will be more comprehensive and readily combined in meta-analyses and that patient care will subsequently be improved. This paper provides guidance on how to use the Harmonising Outcome Measures for Eczema (HOME) initiative's Core Outcome Set. It provides helpful tips based on frequently asked questions and data to inform sample size calculations. To encourage transparent reporting, a template for reporting trial outcome data is provided.