T-VASI and F-VASI may Track Meaningful improvement in nonsegmental Vitiligo, confirms Study

According to the study, the T-VASI and F-VASI have proven reliable and valid assessment tools that distinguish between different clinical groups and effectively track changes in patients with nonsegmental vitiligo.

"Notably, the study found that the thresholds for meaningful change are lower than those typically established in clinical trials. This indicates that T-VASI 50 and F-VASI 75 serve as conservative benchmarks, capturing improvements that are genuinely significant for patients managing nonsegmental vitiligo," the researchers wrote.

Establishing meaningful improvement through the T-VASI and the F-VASI enhances the interpretation of results from clinical trials assessing vitiligo treatments. However, definitive and clinically significant thresholds for these measures have yet to be established. To address this knowledge gap, Khaled Ezzedine, Department of Dermatology, Hôpital Henri Mondor, Assistance Publique–Hôpitaux de Paris, Créteil, France, and colleagues aimed to evaluate the concept validity and measurement effectiveness of the T-VASI and F-VASI in patients with nonsegmental vitiligo, while also identifying thresholds for meaningful change.

For this purpose, the researchers conducted a mixed-methods study that analyzed data from a phase 2 multicenter, double-blind trial involving adult patients with nonsegmental vitiligo across 35 sites in Canada, France, Japan, and the US. Participants were randomized to receive 6-, 11-, or 22-mg/day upadacitinib or placebo for 24 weeks.

The study assessed the psychometric performance of the Total Vitiligo Area Scoring Index and Facial VASI, along with thresholds for meaningful change, using clinician- and patient-reported data. Qualitative interviews evaluated content validity and patient perceptions of meaningful repigmentation. Data analyses were conducted between March and July 2023.

The study led to the following findings:

• The psychometric analysis involved 164 participants, averaging 46 years old (63% female), while the qualitative analysis included 14 participants with an average age of 48.8 years (64% female, 36% male).
• Intraclass correlation coefficients indicated strong test-retest reliability: 0.98 for T-VASI and 0.99 for F-VASI between baseline and week 4.
• At baseline and week 24, correlations were moderate to strong: T-VASI with PhGVA-T (r = 0.63-0.65) and F-VASI with PhGVA-F (r = 0.65-0.71).
• Average VASI scores decreased with repigmentation, and least-square mean scores increased with greater improvement as measured by PhGIC-V.
• A 30% improvement in T-VASI and a 50% improvement in F-VASI scores were identified as meaningful changes from baseline to week 24.

The study validates the measurement properties of the Total Vitiligo Area Scoring Index (T-VASI) and Facial VASI (F-VASI) and highlights the clinical significance of the concepts they encompass. The randomized controlled trial data indicate that improvements of as little as 30% in T-VASI and 50% in F-VASI can be viewed as meaningful changes for patients.

"Consequently, the established thresholds of 50% improvement for T-VASI and 75% for F-VASI, as suggested by Kitchen et al., are effective for capturing patients' perceptions of meaningful change in vitiligo treatment trials. Thus, both T-VASI and F-VASI are suitable tools for use in clinical trials focusing on patients with nonsegmental vitiligo," the researchers concluded.

Reference:

Ezzedine K, Soliman AM, Camp HS, et al. Psychometric Properties and Meaningful Change Thresholds of the Vitiligo Area Scoring Index. JAMA Dermatol. Published online October 30, 2024. doi:10.1001/jamadermatol.2024.4534