Hidradenitis Suppurativa Area and Severity Index Revised (HASI-R): psychometric property assessment

Br J Dermatol. 2021 May;184(5):905-912. doi: 10.1111/bjd.19565. Epub 2020 Dec 30.


Background: Validated, reliable, globally accepted outcome measurement instruments for hidradenitis suppurativa (HS) are needed. Current tools to measure the physical signs domain for HS rely on lesion counts, which are time-consuming and unreliable.

Objectives: To assess the reliability and validity of the Hidradenitis suppurativa Area and Severity Index Revised (HASI-R) tool, a novel method for assessing HS severity, incorporating signs of inflammation and body surface area involved.

Methods: The measurement properties of the HASI-R tool were evaluated. The tool was created by combining the previously published HASI and Severity and Area Score for Hidradenitis instruments. Twenty raters evaluated 15 patients with HS in a hospital-based ambulatory dermatology clinic. The objectives of the study were to assess inter- and intra-rater reliability of the HASI-R and its components, as well as its construct and known-groups validity. Existing lesion count-based clinician-reported measures of HS and their components were also assessed. Raters were also asked their preferences regarding the various HS severity assessment tools.

Results: The HASI-R had moderate inter-rater reliability [intra-class correlation coefficients (ICC) 0·60]. This was better than all other HS physical sign outcome measures evaluated, which had poor inter-rater reliability (ICC < 0·5). HASI-R had the highest intra-rater reliability (ICC 0·91). The HASI-R had good construct validity and demonstrated known-groups validity. The HASI-R was also the most preferred tool by all raters.

Conclusions: Results from the clinometric assessment of the HASI-R are encouraging, and support continued evaluation of this clinician-reported outcome measure.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Hidradenitis Suppurativa* / diagnosis
  • Humans
  • Psychometrics
  • Reproducibility of Results
  • Severity of Illness Index