1239 Validation of an objective measurement algorithm for facial vitiligo

Background: Facial repigmentation is the main primary outcome measure of most trials assessing new treatments for vitiligo. Objective: To assess validity and reliability an objective measurement method percent depigmentation vitiligo lesions on face. Methods: Multicentric cross-sectional prospective trial. 22 consecutive patients presenting with facial were included. Depigmentation was analyzed before any treatment, 7 them after 3 6 months narrowband ultraviolet B treatment combined 16mg methylprednisolone, both used twice weekly. A dedicated algorithm performed standardized UV picture developed. Facial-VASI (F-VASI) percentage depigmented skin then assessed by 13 dermatologists, including experts in grading compared algorithm. Results: total 31 sets pictures analyzed. Internal validation showed excellent reproducibility a variation <3%. The system correlated well dermatologists (R2=0.77 non-expert group R2=0.70 expert group). intraclass correlation coefficient (ICC) F-VASI 0.44 0.52 non-experts experts, respectively. When results separately homogeneous heterogeneous depigmentation, ICC 0.47 0.84 0.19 0.48 Conclusions: This study underlines limitations score when all cases heterogeneous. It also demonstrates that Vitil-IA provides accurate reproducible assessment involvement