Short-Term Correlation of the Psoriasis Area Severity Index, the Nail Psoriasis Area Severity Index, and the Dermatology Life Quality Index, before and after Treatment, in Patients with Skin and Nail Psoriasis.

BACKGROUND: The response to treatment in patients suffering from skin and nail psoriasis is quantitatively evaluated by monitoring clinical severity and quality of life indexes, especially in the context of clinical trials. Among them, the psoriasis area severity index (PASI), the nail psoriasis area severity index (NAPSI), and the dermatology life quality index (DLQI) are currently the most widely used indexes. OBJECTIVE: To study the short-term correlation between PASI, NAPSI, and DLQI in patients with skin and nail psoriasis at baseline and 3 months after treatment initiation. MATERIALS AND METHODS: This is a 2-center prospective, observational, cross-sectional study of 40 treatment-naive patients suffering from chronic plaque psoriasis with nail involvement and requiring systemic therapy. Disease activity and quality of life were assessed at baseline and 3 months after treatment initiation by measuring PASI, NAPSI, and DLQI scores. Statistical correlations between theses indexes were investigated using the appropriate statistical tests. RESULTS: A positive, strong correlation was observed between DLQI and NAPSI at baseline (r = 0.579, p <0.001) and at 3 months (r = 0.484, p = 0.002). Similarly, a strong correlation was noted between DLQI and PASI at baseline (r = 0.496, p = 0.001) and at 3 months (r = 0.401, p = 0.01). Moreover, we observed a positive strong correlation (r = 0.515, p = 0.001) between DLQI at baseline and NAPSI at 3 months and a moderate correlation (r = 0.433, p = 0.005) between DLQI at baseline and PASI at 3 months. CONCLUSION: The observed positive correlations between PASI, NAPSI, and DLQI provide further evidence in support of their simultaneous utilization in clinical studies for skin and nail psoriasis. Moreover, the predictive value of DLQI at baseline emphasizes the importance of quality of life assessment when designing a therapeutic study as well as in the everyday clinical practice.