Psychometric evaluation of skin pain and sleep disturbance numeric rating scales in moderate-to-severe atopic dermatitis

Abstract

INTRODUCTION: Atopic dermatitis (AD) is a chronic inflammatory skin condition often associated with skin pain and sleep disturbance. The AD Skin Pain Numeric Rating Scale (SP-NRS) and Sleep Disturbance NRS (SD-NRS) are single-item patient-reported outcome measures developed to assess AD-related skin pain and sleep disturbance severity, respectively, in AD clinical trials.

METHODS: We used data from three randomized, double-blinded, placebo-controlled clinical trials of rocatinlimab in adults (aged ≥ 18 years) (ROCKET-IGNITE and ROCKET-SHUTTLE) and adolescents (aged ≥ 12 to < 18 years) (ROCKET-ASTRO) with moderate-to-severe AD to assess the reliability, validity, and responsiveness of the AD SP-NRS and SD-NRS. Clinical outcome assessments (COAs) supported the psychometric evaluation, and we estimated meaningful change thresholds for the AD SP-NRS and SD-NRS using anchor-based methods, which we confirmed with distribution-based methods. We included data from both the treatment arm and placebo in our analyses, and we analyzed results from adult and adolescent populations separately.

RESULTS: This psychometric analysis sample used 262 adults (ROCKET-IGNITE, n = 145; ROCKET-SHUTTLE, n = 117) and 109 adolescents (ROCKET-ASTRO, n = 109), subsets from the initial data cuts of the respective clinical trials, in the psychometric analysis sample. Both AD SP-NRS and SD-NRS scores demonstrated high test-retest reliability for both adults and adolescents (intraclass correlation coefficients ≥ 0.80) and moderate-to-strong (|r| ≥ 0.30) positive correlations with most supporting COAs. Anchor-based meaningful within-patient change threshold ranges derived for AD SP-NRS and SD-NRS scores supported both 3-point and 4-point improvement thresholds for characterizing clinically meaningful changes.

CONCLUSIONS: The AD SP-NRS and SD-NRS are reliable, valid, and responsive measures for assessing moderate-to-severe AD in adults and adolescents in clinical trials. The meaningful change thresholds identified in this study can be used in future clinical trials to interpret treatment effects.