Reliability and validity of the Vitiligo Signs of Activity Score (VSAS)

Area of Science:

• Dermatology
• Clinical assessment tools
• Vitiligo research

Background:

• Vitiligo disease activity is associated with clinical signs, but a validated scoring system is absent.
• Existing evidence suggests a link between visible signs and vitiligo activity.

Purpose of the Study:

• To validate the physician-based Vitiligo Signs of Activity Score (VSAS).
• To establish a standardized method for quantifying visible clinical signs of vitiligo activity.

Main Methods:

• Scored three clinical signs (confetti-like depigmentation, Koebner phenomenon, hypochromic areas/borders) across 15 body locations.
• Assessed inter- and intrarater reliability of the global VSAS and its subscores.
• Evaluated construct validity and feasibility, including rater completion time.

Main Results:

• The VSAS demonstrated good inter-rater reliability (ICC 0.87-0.90) and excellent intrarater reliability (ICC ≥ 0.86).
• Subscores showed excellent reliability for confetti-like depigmentation and fair reliability for Koebner phenomenon and hypochromic areas/borders.
• Feasibility was confirmed with a median completion time of 1.33 minutes per patient after initial rounds.

Conclusions:

• The VSAS is a valid and reliable instrument for standardized scoring of visible clinical signs linked to vitiligo disease activity.
• The VSAS can aid in quantifying disease activity in clinical practice and trials.
• This tool may facilitate future research on the clinical significance of specific vitiligo signs.