Both 3-point and 4-point reductions on the Skin Pain Numeric Rating Scale and Sleep Disturbance Numeric Rating Scale represent clinically meaningful improvement in patients with moderate-to-severe atopic dermatitis, according to a psychometric analysis published in Dermatology and Therapy.
The analysis used blinded data from three phase 3 trials of rocatinlimab—the ROCKET-IGNITE, ROCKET-SHUTTLE, and ROCKET-ASTRO studies—which enrolled 262 adult and 109 adolescent patients with moderate-to-severe atopic dermatitis (AD). Investigators examined how changes on the AD Skin Pain Numeric Rating Scale (SP-NRS) and Sleep Disturbance Numeric Rating Scale (SD-NRS) align with patients' perceptions of improvement. Both are single-item, 11-point scales that ask patients to rate symptom severity over the previous 24 hours.
Although itch and visible disease severity are central to AD assessment, patients frequently report skin pain and disrupted sleep as distinct and burdensome symptoms. These concerns do not always improve in parallel with itch or lesion scores, making them important outcomes in their own right.
Across age groups, the results consistently supported 3-point and 4-point reductions on both scales as thresholds for clinically meaningful within-patient improvement. In practical terms, a 3-point reduction represents a noticeable improvement in skin pain or sleep quality from the patient's perspective, while a 4-point reduction reflects a more substantial benefit. For comparing treatment groups, the analysis supported a range of 1 to 3 points as the between-group minimal important difference threshold.
Both the SP-NRS and SD-NRS demonstrated high test-retest reliability, with intraclass correlation coefficients of at least 0.80 in adult and adolescent patients. The scales also showed moderate-to-strong correlations with related patient-reported measures, including the Patient Global Impression of Severity and the SCORing Atopic Dermatitis sleep loss visual analog scale. Correlations with clinician-assessed severity scores were weaker, confirming that skin pain and sleep disturbance capture patient experiences that are not fully reflected in clinical examination.
The findings reinforce why skin pain and sleep disturbance should be considered separately from itch and lesion severity. Some patients continue to report painful skin or poor sleep despite improvements in itch or clinical signs, highlighting the limitations of relying on a single outcome to assess treatment benefit.
These results provide a framework for physicians interpreting efficacy data. When a trial reports average improvements of 3 or 4 points in skin pain or sleep disturbance, these changes can be viewed as meaningful to patients. Between-group differences of 1 to 3 points can help determine whether one treatment provided a clinically relevant advantage over another for these specific symptoms.
"The AD SP-NRS and SD-NRS are fit-for-purpose endpoint measures for evaluating AD skin pain and sleep disturbance severity, respectively, in clinical trials, and the meaningful change thresholds generated in this study can be considered for efficacy analyses of future clinical trials to help contextualize treatment effects," wrote Kimberly M. Deininger, of Amgen Inc., and colleagues.
Full disclosures are available in the published article.
Source: Dermatology and Therapy
