Psychometric Validation and Responder Definition of Sleep Disturbance Numerical Rating Scale in Moderate-To-Severe Atopic Dermatitis.

BACKGROUND Sleep disturbance (SD) is an important part of the burden of atopic dermatitis (AD), but patient-reported outcomes that are easy to understand and interpret in the target population have been lacking. A daily, single-item, self-reported SD 11-point numerical rating scale (NRS) was recently developed to assess SD for patients with moderate-to-severe AD, but its psychometric properties have not yet been described. OBJECTIVE Assess the psychometric properties of the SD NRS in patients with moderate-to-severe AD. METHODS Psychometric properties of the SD NRS were assessed using data from a phase IIb clinical trial in 218 adults with moderate-to-severe AD. RESULTS Test-retest reliability of the SD NRS was substantial to almost-perfect (interclass correlation=0.66-1.00) in participants who had stable SD or stable pruritus scores over 1 week. Baseline correlations were moderate to large (r > 0.30) between SD NRS and pruritus or sleep loss scores but were small (r=-0.11-0.17) between SD NRS and EQ-5D-3L index and visual analogue scores, HADS scores, SCORAD scores, and investigator's global assessment scores. The SD NRS could discriminate groups of participants in the expected direction according to different quality-of-life scores but not according to different clinician-reported disease severity scores. SD NRS scores significantly decreased as sleep loss, itch, and quality of life scores improved. Analysis of meaningful change suggested a 2- to 5-point improvement as the initial range of responder definition in the SD NRS score. CONCLUSIONS The SD NRS is a reliable, valid, and responsive measure of SD in adults with moderate-to-severe AD.