A pilot study on the Psoriasis Area and Severity Index (PASI) for small areas: Presentation and implications of the Low PASI score

• Published in: The Journal of dermatological treatment Vol. 26; no. 4; pp. 314 - 317
• Main Authors: Otero, M. E., van Geel, M. J., Hendriks, J. C. M., van de Kerkhof, P. C. M., Seyger, M. M. B., de Jong, E. M. G. J.
• Format: Journal Article
• Language: English
• Published: England Informa Healthcare 04.07.2015
• Subjects: Adolescent; Adult; Aged; Body surface area; Cross-Sectional Studies; Female; Humans; Male; Middle Aged; PASI; Pilot Projects; psoriasis; Psoriasis - pathology; Psoriasis - therapy; Psoriasis Area and Severity Index; Severity of Illness Index; Young Adult; PASI; Body surface area; Psoriasis Area and Severity Index; psoriasis
• ISSN: 0954-6634; 1471-1753
• DOI: 10.3109/09546634.2014.972316

Background: The Psoriasis Area and Severity Index (PASI) is not able to measure small affected areas in a body region which is important for assessing the performance of high-effective treatment. Objective: To present the Low PASI score, show the difference between the classic PASI and the Low PASI, evaluate the inter-observer agreement of both scores, and compare the two scores within investigators. Methods: Cross-sectional study. Two investigators independently assessed the classic PASI and the Low PASI in 10 patients with mild-to-moderate plaque psoriasis. Differences in outcome between the two scores were calculated. Intra-class correlation coefficients (ICC) were used to determine the inter-observer agreement and to compare measurements of the two scores within both investigators. Prediction limits of 95% for the errors in measurements were provided. Results: In both investigators, Low PASI was mean 1.71 and 1.76, whereas the classic PASI was mean 4.14 and 4.33. The inter-observer agreement (ICC) was excellent for both investigators in both scores (ICC classic PASI = 0.95 and Low PASI = 0.87). Conclusion: The Low PASI score allows more possible scores at lower levels of psoriasis extent (affected areas lower than 10% in a body region) compared to the classic PASI. This new score may lead to a more precise analysis of treatment responses and may have important clinical implications.