Comparison of NAPSI and N-NAIL for evaluation of fingernail psoriasis in patients with moderate-to-severe plaque psoriasis treated using ustekinumab

Objective: We sought to determine the psoriatic nail feature which responds to ustekinumab treatment more effectively, and evaluate which between the Nail Psoriasis Severity Index (NAPSI) and the Nijmegen-Nail psoriasis Activity Index tooL (N-NAIL) better reflects the clinical improvement of nail psoriasis.

Methods: Thirty patients with moderate-to-severe plaque psoriasis were prospectively enrolled and treated with ustekinumab for 52 weeks. A single investigator evaluated the condition using the NAPSI and the N-NAIL with serial fingernail photographs.

Results: Of the 30 patients, 13 (43.3%) had fingernail psoriasis present at baseline. Mean NAPSI scores improved from 9.46 ± 8.7 at baseline to 6.00 ± 5.2 at week 52, but the improvement was not statistically significant (p = .09). Mean N-NAIL scores significantly improved from 5.46 ± 5.1 at baseline to 3.92 ± 3.7 at week 52 (p = .04). Of the psoriatic nail features, only the splinter hemorrhages significantly improved at week 52 compared to baseline.

Conclusions: When comparing the mean scores between week 0 and 52, the N-NAIL score (p = .04) better reflected a significant improvement of nail psoriasis than the NAPSI (p = .09), and ustekinumab treatment resulted in a more rapid and effective improvement of splinter hemorrhages.