Erythema of Rosacea: Validation of Patient’s Self-Assessment Grading Scale

Rosacea is a common and chronic skin disorder affecting an estimated 16 million people in the United States.¹ Rosacea primarily affects the central facial area (ie, cheeks, nose, chin, forehead, and eyes) and while various cutaneous signs may be present, such as flushing, visible blood vessels, papules, and pustules, facial erythema is the primary feature of rosacea and presents ubiquitously among patients.^1,2,3

Facial erythema assessments are a common endpoint in rosacea clinical trials and a variety of methods exist to evaluate the erythema of rosacea. Examples include: a single scale for erythema grading in rosacea proposed by the National Rosacea Society, rosacea investigator’s global assessment scales with erythema sections, reflectance spectrophotometry, and visual analogue scales.^4,5,6,7 In order to standardize diagnosis, evaluation, and treatment of rosacea, responsive, discriminatory, and validated outcome measures are needed to assess the signs and symptoms of rosacea, including erythema.⁸ However, the only validated scale available to evaluate the erythema of rosacea is a 5-point numeric rating scale developed as a tool to allow clinician’s to provide an assessment of visible changes to the facial erythema associated with rosacea.⁹ Currently, no validated scales exist that can accurately capture a patient’s self-assessment of their own facial erythema.

Currently, only 1 FDA-approved pharmacologic treatment has been developed for and is indicated to treat the persistent erythema of rosacea (brimonidine topical gel 0.33% (“BT gel”), Galderma Laboratories, L.P.). During phase 2 studies for BT gel, a 5-point numeric rating scale was specifically developed as a patient based measure to allow subjects to provide an independent assessment of facial erythema associated with their rosacea. This patient’s self-assessment (“PSA”) scale was developed with the input of subjects with clinical diagnoses of rosacea and nontransient facial erythema. An initial cross-sectional, qualitative phase of this study was conducted to validate the content of the PSA scale and to ensure that subjects understood the ratings and the instructions. Subjects were interviewed for 1 hour, in person, which included asking subjects to complete a PSA scale and 3 additional versions with alternate descriptions for each grade. After reviewing the 3 scales, subjects were asked for their overall impression of the alternate versions. Interview sessions were audio-recorded and later transcribed for analysis. The wording of the scale was subsequently refined based on the feedback of the subjects. The objective of the study presented here was to validate the revised PSA scale (Table 1) and evaluate it for statistical reliability and validity in quantification of facial erythema of rosacea. This PSA scale was validated based on data of a Phase 2b study on BT gel for the treatment of persistent facial erythema of rosacea.¹⁰