A systematic review of Investigator Global Assessment (IGA) in atopic dermatitis (AD) trials: Many options, no standards

Background: Investigators often use global assessments to provide a snapshot of overall disease severity in dermatologic clinical trials. Although easy to perform, the frequency of use and standardization of global assessments in studies of atopic dermatitis (AD) is unclear. Objectives: We sought to assess the frequency, definitions, and methods of analysis of Investigator Global Assessment in randomized controlled trials of AD. Methods: We conducted a systematic review using all published randomized controlled trials of AD treatments in the Global Resource of Eczema Trials database (2000-2014). We determined the frequency of global scales application and defining features. Results: Among 317 trials identified, 101 trials (32%) used an investigator-performed global assessment as an outcome measure. There was large variability in global assessments between studies in nomenclature, scale size, definitions, outcome description, and analysis. Both static and dynamic scales were identified that ranged from 4- to 7-point scales. North American studies used global assessments more commonly than studies from other countries. Limitations: The search was restricted to the Global Resource of Eczema Trials database. Conclusion: Global assessments are used frequently in studies of AD, but their complete lack of standardized definitions and implementation preclude any meaningful comparisons between studies, which in turn impedes data synthesis to inform clinical decision-making. Standardization is urgently required.