VITILIGO is a chronic autoimmune skin condition affecting between 0.5% –2.0% of the global population, characterised by depigmentation that often leads to visible patches on the skin. Nonsegmental vitiligo, the most common form, can cover large areas of the body, significantly impacting individuals’ mental and emotional health. People with vitiligo frequently experience depression, anxiety, and low self-esteem due to the visibility of the condition, often leading to social stigma and isolation.
In clinical trials for vitiligo treatments, measuring the effectiveness of repigmentation is crucial. The Vitiligo Area Scoring Index (VASI) serves as a clinician-reported metric that assesses the affected body surface area by calculating hand-sized units of depigmentation. The Total VASI (T-VASI) reflects the overall extent of body depigmentation, while the Facial VASI (F-VASI) is used to assess changes in facial depigmentation. Both T-VASI and F-VASI have demonstrated strong reliability and sensitivity, making them suitable tools for tracking progress in patients with nonsegmental vitiligo.
Defining meaningful improvement in vitiligo repigmentation is complex. In earlier studies, a 50-75% repigmentation threshold was considered a meaningful response. However, more recent data suggest that lower thresholds, such as a 42% reduction in T-VASI and a 57% reduction in F-VASI, also correspond to patients’ impressions of substantial improvement. These findings align with patient perspectives, indicating that even partial repigmentation can meaningfully improve quality of life.
The study further emphasised that lower thresholds, such as a 30% T-VASI and 50% F-VASI improvement, can detect clinically relevant changes, allowing a nuanced understanding of treatment responses. Although VASI is widely used, it may show variability between observers, which could affect consistency across clinical trials. Nonetheless, these metrics remain highly reproducible within patients.
Overall, these findings confirm the usefulness of T-VASI and F-VASI in clinical trials, providing reliable thresholds for assessing the effectiveness of vitiligo treatments. Ensuring that these patient-centred improvements are integrated into trial endpoints helps align clinical outcomes with patients’ experiences, supporting a comprehensive approach to vitiligo treatment.
Reference
Ezzedine K et al. Psychometric properties and meaningful change thresholds of the vitiligo area scoring index. JAMA Dermatol. 2024;DOI:10.1001/jamadermatol.2024.4534.
