A newly developed validated Investigator Global Assessment (IGA) atopic dermatitis (AD) scale, accompanied by a training video, demonstrated strong reliability for assessing severity of AD in study research published in the Journal of the American Academy of Dermatology.
A total of 24 global academic and industry dermatologists with expertise in AD formed an advisory group to develop the validated IGA AD (vIGA-AD™) scale. The scale developed by the expert dermatologists measured improvement in clinical signs of AD, which represents the priority domain in drug registration studies. Clinical signs included erythema, lichenification, induration/papulation, and oozing/crusting. Morphological descriptors, as recommended by the FDA, described clearly distinct categories for clear (absence of disease), almost clear (IGA score of 1), and mild disease (IGA score of 2).
Participants in the advisory group undertook 2 surveys approximately 5 months apart to assess the reliability of the scale. The first survey included 35 photographs of patients plus 5 duplicated photographs that were slightly modified. The second survey included 25 photographs of patients as well as a training video that guided dermatologists on the use of the vIGA-AD prior to rating the lesions. A video training module and exam were also developed for a clinical certification exam.
The expert advisory groups reached a consensus for a 5-point IGA scale that included morphological descriptions for each score. The scores include 0 for clear, 1 for almost clear, 2 for mild, 3 for moderate, and 4 for severe disease. Content validity was established for the scale.
In survey 1, strong inter-rater reliability was demonstrated (Kendall’s coefficient of concordance W [Kendall’s W] = 0.809, intra-class correlation [ICC] = 0.817). Survey 1 also demonstrated excellent agreement (weighted Kappa = 0.857). In survey 2, there were noticeable improvements in scale reliability 5 months after training (Kendall’s W = 0.819, ICC = 0.852, weighted Kappa = 0.889). A total of 627 investigators completed training and certification for using the vIGA-AD.
A limitation of the IGA development process was the use of photographs for clinical ratings, which prevented the panel from examining other physical characteristics that would be seen in a physical examination.
The investigators of the study wrote that they “envision that the vIGA-AD will become the standardized IGA to be implemented in future AD clinical trials.”
Disclosure: This clinical trial was supported by Eli Lilly and Company. Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Simpson E, Bissonnette R, Eichenfield LF, et al. The validated Investigator Global Assessment for Atopic Dermatitis (vIGA-AD™): The development and reliability testing of a novel clinical outcome measurement instrument for the severity of atopic dermatitis [published online April 25, 2020]. J Am Acad Dermatol. doi: 10.1016/j.jaad.2020.04.104