Development and Validation of a Composite Skin Quality Scale

Abstract

Background: The increasing demand for skin quality interventions in aesthetic medicine underscores the necessity for objective, evidence-based assessment tools that may be used to evaluate novel interventions or devices.

Objectives: To develop and validate a 5-point photonumeric rating scale for assessing overall skin quality, including radiance, color evenness, and smoothness.

Methods: The IBSA (Institut Biochimique SA) Composite Skin Quality Scale was developed and underwent live validation with 88 real-world patients, chosen to encompass a broad spectrum of skin qualities and Fitzpatrick skin types. Scale validation was performed by board-certified plastic surgeons and dermatologists over 2 rounds, 2 weeks apart. Reliability was assessed through intrarater and interrater agreements, utilizing weighted kappa statistics and intraclass correlation coefficient (ICC). The scale's ability to discern a clinically relevant 1-grade difference was evaluated with 72 photo pairs.

Results: Combined intrarater reliability results showed weighted kappa values of 0.812 (right side) and 0.815 (left side) and an ICC of 0.903 for both sides, indicating an almost perfect agreement. Interrater reliability ranged from substantial to almost perfect, with kappa coefficients between 0.654 and 0.853 and ICCs between 0.657 and 0.855 across all rater pairs in both rounds. The ability to detect a clinically relevant 1-point difference using the scale was established.

Conclusions: Integrating various key aspects of skin quality, the IBSA Composite Skin Quality Scale is a clinically relevant and highly reliable tool, suitable for skin assessment in clinical studies of new aesthetic technologies and products.

Figure 1.

This 5-point photonumeric scale, developed by IBSA (Institut Biochimique SA), is utilized for the assessment of overall skin quality, capturing features such as radiance, texture, and color evenness. The scale includes 5 grades, each represented by a column. The first row features digitally morphed images derived from a participant's photograph to illustrate each grade. The remaining 2 rows were populated with unmorphed, actual patient images selected for each grade of skin quality severity. This scale is owned by and licensed for use by IBSA.