Establishing cut-off values for mild, moderate, and severe disease in pemphigus patients using the Pemphigus Disease Area Index.

Pemphigus is a rare and severe autoimmune bullous disease. To evaluate treatment regimens across multiple centers, an objective and universal disease severity index is necessary.1 The Pemphigus Disease Area Index (PDAI) is considered gold-standard for clinical trials;1-3 however, there are conflicting recommendations regarding cut-off values for mild, moderate, and severe disease. Whereas Shimizu et al. defined cut-off values as ≤8 for mild and ≥25 for severe disease,1 Boulard et al. defined mild and severe disease as ≤15 and ≥45, respectively.