Reliability of the Vitiligo Area Scoring Index measurement tool for vitiligo
Aunna Pourang, Indermeet Kohli, Nneamaka Ezekwe, Angela Parks‐Miller, Tasneem F. Mohammad, Richard H. Huggins, Henry W. Lim, Linda S. Deal, Tatjana Lukić, Fan Zhang, Iltefat Hamzavi
Abstract
Background: A reliable instrument is needed to assess vitiligo severity and treatment response. Objective: To assess inter- and intrarater variability and accuracy of the Vitiligo Area Scoring Index among trained raters and to evaluate a proposed Vitiligo Area Scoring Index using equidistant 10% depigmentation increments (VASI 10%). Methods: In this prospective study, 12 raters evaluated images of 10 participants with vitiligo on 2 occasions using total body Vitiligo Area Scoring Index (T-VASI) and facial Vitiligo Area Scoring Index (F-VASI) scores after training. Inter- and intrarater reliabilities and accuracy vs digital scores were determined using intraclass correlation coefficients. VASI 10% scores were evaluated separately for interrater reliability and accuracy. Results: F-VASI interrater reliability improved from "moderate" to "good" between time points, while T-VASI was "good" at both time points. Intrarater reliability ranged from "good" to "excellent" for T-VASI and "poor" to "excellent" for F-VASI. Accuracy intraclass correlation coefficient was "good" to "excellent" for most raters. Interrater reliability using VASI 10% was "moderate" for both T-VASI and F-VASI. Limitations: Small participant population and number of raters; participants were not assessed in person; no repeated VASI 10% measures. Conclusion: Vitiligo Area Scoring Index generally provides good to excellent reliability for assessment of vitiligo by raters who receive standardized training.