Facial photoprotection in xeroderma pigmentosum (XP) patients: Validation of a new self-reported questionnaire of adherence.

Abstract

Adherence to photoprotection is the only way to prevent skin cancers and eye disease in xeroderma pigmentosum (XP). No validated self-report questionnaire exists for assessing adherence to photoprotection practices in individuals with XP. We sought to validate a self-reported measure of adherence to face photoprotection in this population. Sixty six XP patients recruited from the patient list of the XP specialist service in London, UK, completed a questionnaire of adherence to specific photoprotection behaviours. We measured objective ultraviolet radiation (UVR) exposure to the face continuously for 21days with a wristworn UVR electronic dosimeter combined with a daily photoprotection diary. Reliability and convergent validity of the questionnaire were tested in relation to overall UVR exposure, UVR dose to the face, daily photoprotection activities, other self-reported photoprotection practices and clinical ratings of patient's protection. Internal consistency of the questionnaire was satisfactory. Questionnaire total scores were concordant with objective UVR exposure and UVR dose to the face. However, not all participants who reported good/excellent face photoprotection on the questionnaire recorded high levels of photoprotection in the daily diary. Correlations between the questionnaire and other practices and the clinical rating ranged from small to large in size. There was no correlation between the level of face photoprotection and self-reported avoidance of going outside. Our questionnaire was reliable and had good convergent validity with other indicators of photoprotection. This questionnaire could assist clinicians to detect low levels of adherence, and the methodology used to develop validated questionnaires for other photosensitive conditions.