Comparative Assessment of PASI and Variations of PGA×BSA as Measures of Psoriasis Severity. Issue 4 (September 2017)

• Record Type: Journal Article
• Authors: Walsh, Jessica A.; Tan, Huaming; Valdez, Hernan; Duffin, Kristina Callis
• Is Part Of: Journal of psoriasis and psoriatic arthritis. Volume 2:Issue 4(2017)
• Page Start: 113
• Page End: 118
• Publication Date: 2017-09
• Subjects: PASI -- physician's global assessment -- body surface area -- psoriasis -- psoriasis area and severity index -- severity -- tofacitinib -- etanercept; Psoriasis -- Periodicals; Psoriasis -- Treatment -- Periodicals; Psoriatic arthritis -- Periodicals; Psoriatic arthritis -- Treatment -- Periodicals; Electronic journals; 616.722
• DOI: 10.1177/247553031700200409
• Languages: English
• ISSNs: 2475-5303

Abstract

Background: Commonly used instruments for measuring psoriasis, such as Psoriasis Area and Severity Index (PASI), have limitations, including high complexity. Objective: Determine if PGA×BSA or PGA×√BSA are practical alternatives to PASI for measuring severity and treatment response. Methods: Data from a Phase 3 study in 1, 101 patients treated for moderate to severe psoriasis were used. PASI was the reference standard. Correlations (Pearson coefficients), test-retest reliability (intraclass correlation coefficients), responsiveness to treatment (percentage change and effect size), and correspondence (sensitivity and specificity) were assessed. Results: Correlation coefficients of change (baseline at Week 12) were 0.90 between PASI and either PGA×BSA and PGA×√BSA. ICCs were 0.90. Both instruments demonstrated similar percentage change from baseline and effect sizes. Sensitivities of PGA×BSA and PGA×√BSA were 99% and 95%, and specificities were 76% and 87%, respectively. Conclusions: PGA×BSA and PGA×√BSA had similar measurement properties as PASI. PGA×BSA is a practical alternative to PASI.