Development and Validation of Vitiligo-Specific-Belief About Therapy Questionnaire (BTQ-Vitiligo)

Abstract

There is a need to capture therapy-related beliefs held by patients with conditions like vitiligo that have complex treatment regimens. Concerns about adverse effects and uncertainty about response to the prescribed treatment can impact adherence and the perceived treatment burden. This study aims to develop and validate a questionnaire on beliefs about therapy in patients with vitiligo. It is a cross-sectional study. A vitiligo-specific item pool was developed through literature review, in-depth interviews with patients with vitiligo (n = 10), and expert surveys (n = 8). The instrument was studied on 140 patients for psychometric properties using the Vitiligo Treatment Impact score (VITs) and Medication Adherence Rating Scale-5 (MARS-5); self-reported severity using PtGA (Patient Global Assessment) and Response VASI (Vitiligo Area Scoring Index). Exploratory factor analysis demonstrated a six-factor structure with 21 items. Discriminant validity was evidenced by correlation between response VASI and questionnaire subscales (r = −0.538). Correlation with VITs (r = −0.610), MARS-5 (r = 0.453), and PtGA (r = 0.486) demonstrated construct and criterion validity, respectively. BTQ-vitiligo demonstrated test–retest reliability (r = 0.779) during the follow-up visit. BTQ-vitiligo is a validated instrument that helps clinicians understand patients' perspectives about therapy and tailor it accordingly to ensure adherence and further response to therapy. We developed and validated a BTQ-vitiligo, a valuable tool for capturing therapy-related beliefs in vitiligo, a complex dermatological disease with medication challenges. Although several patient-reported outcome measures (PROMs) have been developed to assess various aspects of vitiligo, none exist to capture patients' beliefs about therapy, which is a key determinant of the perceived burden of treatment. Our questionnaire identifies general and specific medication beliefs across six domains, with 21 items included under it.