Photoprotection Habits in Patients With Vitiligo

Intro:

Patients with vitiligo have a reduced protection on depigmented areas. To date, however, little is known about photoprotection habits in patients with vitiligo even though these patients are thought to have a decreased ability to efficiently protect their skin against sun damage. Moreover, exposure to artificial UV is one of the major elements of the treatment of vitiligo even though certain phenotypes of vitiligo could be photoinduced.

Hypothesis The Primary objective is to describe patients behaviour with sun exposition

The Secondary objectives are:

* to assess the link between sun exposition and vitiligo outbreaks * to assess photoprotection habits according to initial phototype and vitiligo severity (SA-VES) * To validate a short form of the VIPs questionnaire, a validated burden questionnaire.

Method We aim to conduct a prospective cross sectional study in patients with Vitiligo with the aim to evaluate sun protection habits in patients with vitiligo. For that purpose a semi-directed questionnaire to investigate the sun protection behavior of vitiligo patients (adults> 18 years of age) have been created by experts in the field. Vitiligo severity will be self-assessed by patients using a recently validated patient reported outcome, the SA-VES. Consecutive vitiligo patients consulting in the dermatology department of Henri Mondor Hospital (Créteil, France) will be proposed to participate the study after having given their oral consent. We are planning to enrol 500 patients.

In a first step, a descriptive analysis will be carried out in order to describe the characteristics of the sample. Basic summary statistics, such as proportions, means and standard deviations, will be used to characterize the population. In order to identify the factors associated with the severity of the disease on the one hand and the phototype on the other, comparisons between groups (severe versus non-severe and light phototype versus dark phototype) will be carried out by unconditional logistic regression. All potential predictors of severity will first be assessed individually, and Odds Ratio (OR), corresponding 95% CIs and P values will be calculated. The significance of the OR will be determined by the Wald test χ2, and the predictors with P <.20 will then be evaluated using a multivariate analysis with a pre-selection procedure. Possible interactions and multi-colinearity will be examined. Finally, the quality of fit of the final model will be evaluated using the logistic regression diagnostic procedure. P ≤ 0.05 will be considered as statistically significant. The Hosmer-Lemeshow test will be carried out to test the suitability of the model.

Conclusion This study will help to identify gaps in the knowledge of sun protection habits in patients with vitiligo.