Validity of an atopic dermatitis outcome measure for real-world clinical practice

Introduction: Atopic dermatitis (AD) is the most common chronic inflammatory skin disease in the United States. AD is associated with reduced quality of life and substantial financial costs, making it burdensome at an individual and population level. Disease severity outcome measures are validated tools to assess severity and therapeutic response. Recent consensus statements have identified gold-standard outcome measures for AD in clinical trials, but further work is needed evaluating outcome measures feasible for clinical practice. Objective: To investigate the validity and feasibility of the product of investigator global assessment and body surface area (IGA x BSA) as an outcome measure for AD in the clinical setting. Methods and Results: Retrospective chart review of patients with AD seen in an outpatient dermatology clinic at Oregon Health & Science University from 2015-2018 with recorded BSA and IGA revealed 246 patients comprising 682 clinic visits. We observed strong and statistically significant correlations between IGA x BSA and the gold-standard measurement for clinical signs in clinical trials, the Eczema Area and Severity Index (r=0.9105, p \u3c0.0001, n=19). IGA x BSA also showed strong correlations with the average daily pruritus numerical rating scale (r=0.7108, p \u3c0.0001, n=177) and the patient global assessment (r=0.7389, p \u3c0.0001, n=170). Conclusions: IGA x BSA is a valid and feasible outcome measure for AD which aligns with patient-reported disease severity and may be used in real-world clinical practice