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Reliability and convergent validity of two outcome instruments for pemphigus.

Publication ,  Journal Article
Rosenbach, M; Murrell, DF; Bystryn, J-C; Dulay, S; Dick, S; Fakharzadeh, S; Hall, R; Korman, NJ; Lin, J; Okawa, J; Pandya, AG; Payne, AS ...
Published in: J Invest Dermatol
October 2009

A major obstacle in performing multicenter controlled trials for pemphigus is the lack of a validated disease activity scoring system. Here, we assess the reliability and convergent validity of the PDAI (pemphigus disease area index). A group of 10 dermatologists scored 15 patients with pemphigus to estimate the inter- and intra-rater reliability of the PDAI and the recently described ABSIS (autoimmune bullous skin disorder intensity score) instrument. To assess convergent validity, these tools were also correlated with the Physician's Global Assessment (PGA). Reliability studies demonstrated an intra-class correlation coefficient (ICC) for inter-rater reliability of 0.76 (95% confirdence interval (CI)=0.61-0.91) for the PDAI and 0.77 (0.63-0.91) for the ABSIS. The tools differed most in reliability of assessing skin activity, with an ICC of 0.39 (0.17-0.60) for the ABSIS and 0.86 (0.76-0.95) for the PDAI. Intra-rater test-retest reliability demonstrated an ICC of 0.98 (0.96-1.0) for the PDAI and 0.80 (0.65-0.96) for the ABSIS. The PDAI also correlated more closely with the PGA. We conclude that the PDAI is more reproducible and correlates better with physician impression of extent. Subset analysis suggests that for this population of mild-to-moderate disease activity, the PDAI captures more variability in cutaneous disease than the ABSIS.

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Published In

J Invest Dermatol

DOI

EISSN

1523-1747

Publication Date

October 2009

Volume

129

Issue

10

Start / End Page

2404 / 2410

Location

United States

Related Subject Headings

  • Skin
  • Severity of Illness Index
  • Sensitivity and Specificity
  • Reproducibility of Results
  • Pemphigus
  • Pain Measurement
  • Outcome Assessment, Health Care
  • Observer Variation
  • Humans
  • Dermatology & Venereal Diseases
 

Citation

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Rosenbach, M., Murrell, D. F., Bystryn, J.-C., Dulay, S., Dick, S., Fakharzadeh, S., … Werth, V. P. (2009). Reliability and convergent validity of two outcome instruments for pemphigus. J Invest Dermatol, 129(10), 2404–2410. https://doi.org/10.1038/jid.2009.72
Rosenbach, Misha, Dedee F. Murrell, Jean-Claude Bystryn, Sam Dulay, Sarah Dick, Steve Fakharzadeh, Russell Hall, et al. “Reliability and convergent validity of two outcome instruments for pemphigus.J Invest Dermatol 129, no. 10 (October 2009): 2404–10. https://doi.org/10.1038/jid.2009.72.
Rosenbach M, Murrell DF, Bystryn J-C, Dulay S, Dick S, Fakharzadeh S, et al. Reliability and convergent validity of two outcome instruments for pemphigus. J Invest Dermatol. 2009 Oct;129(10):2404–10.
Rosenbach, Misha, et al. “Reliability and convergent validity of two outcome instruments for pemphigus.J Invest Dermatol, vol. 129, no. 10, Oct. 2009, pp. 2404–10. Pubmed, doi:10.1038/jid.2009.72.
Rosenbach M, Murrell DF, Bystryn J-C, Dulay S, Dick S, Fakharzadeh S, Hall R, Korman NJ, Lin J, Okawa J, Pandya AG, Payne AS, Rose M, Rubenstein D, Woodley D, Vittorio C, Werth BB, Williams EA, Taylor L, Troxel AB, Werth VP. Reliability and convergent validity of two outcome instruments for pemphigus. J Invest Dermatol. 2009 Oct;129(10):2404–2410.
Journal cover image

Published In

J Invest Dermatol

DOI

EISSN

1523-1747

Publication Date

October 2009

Volume

129

Issue

10

Start / End Page

2404 / 2410

Location

United States

Related Subject Headings

  • Skin
  • Severity of Illness Index
  • Sensitivity and Specificity
  • Reproducibility of Results
  • Pemphigus
  • Pain Measurement
  • Outcome Assessment, Health Care
  • Observer Variation
  • Humans
  • Dermatology & Venereal Diseases