Advances in Clinical and Experimental Medicine

Adv Clin Exp Med
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Advances in Clinical and Experimental Medicine

2017, vol. 26, nr 5, August, p. 851–856

doi: 10.17219/acem/69804

Publication type: original article

Language: English

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Creative Commons BY-NC-ND 3.0 Open Access

The reliability of three psoriasis assessment tools: Psoriasis area and severity index, body surface area and physician global assessment

Agnieszka Bożek1,A,B,C,D,E,F, Adam Reich1,A,B,C,D,E,F

1 Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Poland


Background. A wide variety of psoriasis assessment tools have been proposed to evaluate the severity of psoriasis in clinical trials and daily practice. The most frequently used clinical instrument is the psoriasis area and severity index (PASI); however, none of the currently published severity scores used for psoriasis meets all the validation criteria required for an ideal score.
Objectives. The aim of this study was to compare and assess the reliability of 3 commonly used assessment instruments for psoriasis severity: the psoriasis area and severity index (PASI), body surface area (BSA) and physician global assessment (PGA).
Material and Methods. On the scoring day, 10 trained dermatologists evaluated 9 adult patients with plaque-type psoriasis using the PASI, BSA and PGA. All the subjects were assessed twice by each physician. Correlations between the assessments were analyzed using the Pearson correlation coefficient. Intra-class correlation coefficient (ICC) was calculated to analyze intra-rater reliability, and the coefficient of variation (CV) was used to assess inter-rater variability.
Results. Significant correlations were observed among the 3 scales in both assessments. In all 3 scales the ICCs were > 0.75, indicating high intra-rater reliability. The highest ICC was for the BSA (0.96) and the lowest one for the PGA (0.87). The CV for the PGA and PASI were 29.3 and 36.9, respectively, indicating moderate inter-rater variability. The CV for the BSA was 57.1, indicating high inter-rater variability.
Conclusion. Comparing the PASI, PGA and BSA, it was shown that the PGA had the highest inter-rater reliability, whereas the BSA had the highest intra-rater reliability. The PASI showed intermediate values in terms of interand intra-rater reliability. None of the 3 assessment instruments showed a significant advantage over the other. A reliable assessment of psoriasis severity requires the use of several independent evaluations simultaneously.

Key words

psoriasis, measurement tools, PGA, BSA, PASI

References (16)

  1. Kupetsky EA, Keller M. Psoriasis vulgaris: An evidence-based guide for primary care. J Am Board Fam Med. 2013;26:787–801.
  2. Spuls PI, Lecluse LL, Poulsen ML, Bos JD, Stern RS, Nijsten T. How good are clinical severity and outcome measures for psoriasis?: Quantitative evaluation in a systematic review. J Invest Dermatol. 2010;130:933–943.
  3. Naldi L, Svensson A, Diepgen T, et al. Randomized clinical trials for psoriasis 1977–2000: The EDEN survey. J Invest Dermatol. 2003;120:738–741.
  4. Chularojanamontri L, Griffiths CE, Chalmers RJ. Responsiveness to change and interpretability of the simplified psoriasis index. J Invest Dermatol. 2014;134:351–358.
  5. Naldi L. Scoring and monitoring the severity of psoriasis. What is the preferred method? What is the ideal method? Is PASI passé? Facts and controversies. Clin Dermatol. 2010;28:67–72.
  6. Puzenat E, Bronsard V, Prey S. What are the best outcome measures for assessing plaque psoriasis severity?: A systematic review of the literature. J Eur Acad Dermatol Venereol. 2010;24(Suppl 2):10–16.
  7. Fredriksson T, Pettersson U. Oral treatment of pustulosis palmo-plantaris with a new retinoid, Ro 10-9359. Dermatologica. 1979;158:60–64.
  8. Berth-Jones J, Grotzinger K, Rainville C, et al. A study examining inter- and intrarater reliability of three scales for measuring severity of psoriasis: Psoriasis area and severity index, physician global assessment and lattice system physician global assessment. Br J Dermatol. 2006;155:707–713.
  9. Robinson A, Kardos M, Kimball AB. Physician global assessment (PGA) and psoriasis area and severity index (PASI): Why do both? A systematic analysis of randomized controlled trials of biologic agents for moderate to severe plaque psoriasis. J Am Acad Dermatol. 2012;66:369–375.
  10. Feldman S, Krueger G. Psoriasis assessment tools in clinical trials. Ann Rheum Dis. 2005;64(Suppl 2):65–68.
  11. Chalmers RJ. Assessing psoriasis severity and outcomes for clinical trials and routine clinical practice. Dermatol Clin. 2015;33:57–71.
  12. Berth-Jones J, Thompson J, Papp K. Copenhagen Psoriasis Working Group. A study examining inter-rater and intrarater reliability of a novel instrument for assessment of psoriasis: The Copenhagen psoriasis severity index. Br J Dermatol. 2008;159:407–412.
  13. Langley RG, Ellis CN. Evaluating psoriasis with psoriasis area and severity index, psoriasis global assessment, and lattice system physician global assessment. J Am Acad Dermatol. 2004;51:563–569.
  14. Ramsay B, Lawrence CM. Measurement of involved surface area in patients with psoriasis. Br J Dermatol. 1991;124:565–570.
  15. Yune YM, Park SY, Oh HS, et al. Objective assessment of involved surface area in patients with psoriasis. Skin Res Technol. 2003;9:339–342.
  16. Rhodes J, Clay C, Phillips M. The surface area of the hand and the palm for estimating percentage of total body surface area: Results of a meta-analysis. Br J Dermatol. 2013;169:76–84.