Determining Severity Strata for Three Atopic Dermatitis Patient-Reported Outcome Questionnaires: Defining Severity Score Ranges for the Worst Pruritus Numerical Rating Scale and the Atopic Dermatitis Symptom and Impact Scales (ADerm-SS and ADerm-IS)

Introduction: Three patient-reported outcome (PRO) questionnaires—Worst Pruritus Numerical Rating Scale (WP-NRS), Atopic Dermatitis Symptom Scale (ADerm-SS), and Atopic Dermatitis Impact Scale (ADerm-IS)—were developed to assess the symptoms and impacts of atopic dermatitis (AD). Severity strata for these PROs are needed to aid in their interpretation. Methods: Using data from a global, randomized, double-blind, placebo-controlled, phase 3 clinical trial (NCT03568318) of patients with moderate–severe AD (age ≥ 12 years), equipercentile linking analyses were conducted to define severity strata applying the Patient Global Impression of Severity as an anchor. Analyses were conducted separately for adults and adolescents, and then harmonized between the two age groups. Results: The sample included 769 adults and 113 adolescents. For the WP-NRS, 0 was associated with absent, 1–2 with minimal, 3 with mild, 4–7 with moderate, and 8–10 with severe. For the ADerm-SS Skin Pain, 0 was associated with absent, 1 with minimal, 2 with mild, 3–6 with moderate, and 7–10 with severe. For ADerm-SS 7-Item Total Symptom Score (TSS-7), 0–1 was associated with absent, 2–11 with minimal, 12–22 with mild, 23–47 with moderate, and 48–70 with severe. For ADerm-IS Sleep, 0 was associated with absent, 1–3 with minimal, 4–6 with mild, 7–20 with moderate, and 21–30 with severe. For ADerm-IS Daily Activities, 0 was associated with absent, 1–2 with minimal, 3–7 with mild, 8–25 with moderate, and 26–40 with severe. For ADerm-IS Emotional State, 0 was associated with absent, 1–2 with minimal, 3–8 with mild, 9–22 with moderate, and 23–30 with severe. Conclusions: These severity strata provide score interpretations of the WP-NRS, ADerm-SS, and ADerm-IS, translating these scores to simple and intuitive outcomes, which can inform clinical studies and clinical practice. Trial Registration Number: NCT03568318.