Validation of global item for assessing impact on quality of life of patients with hidradenitis suppurativa

Background Hidradenitis suppurativa (HS) is a chronic inflammatory disease. TheHS core outcome set calls for a patient global assessment (PtGA).Objectives To assess the validity, reliability and responsiveness of a candidate sin-gle-item PtGA for HS-specific health-related quality of life (HRQoL).Methods Cognitive debriefing interviews were conducted with patients with HS in Denmark and the USA. A cross-sectional observational study was done with adults with HS in the USA and Denmark. Candidate PtGA item, demographic items and multiple patient-reported scales–the Hidradenitis Suppurativa Qualityof Life (HiSQOL), Dermatology Life Quality Index (DLQI) and numerical ratingscale (NRS) for pain–were concurrently administered to evaluate convergent and known-groups validity. Scales with a single-item assessment of change were readministered 24–72 h later, to evaluate reliability and responsiveness. Results After cognitive debriefing, the candidate PtGA for HS-specific HRQoL was finalized with five response levels. Convergent validity of the PtGA was supportedby significant correlations with HiSQOL score [r=079, 95% confidence interval(CI) 075–082] and DLQI (r=078, 95% CI 074–082). The PtGA displayed known-groups validity with DLQI score bands based on significance of an ANOVA(P<0001). Good test–retest reliability was supported by the intraclass correlation coefficient (082, 95% CI 078–085) for those who reported stable HS. Responsiveness was assessed by differences in PtGA score against a patient-re-ported assessment of change, which showed significant differences towards improvement. ConclusionsThe single-item PtGA exhibits reliability, validity and responsiveness in assessing HS-specific HRQoL in HS, making it a good provisional tool for HS clinical research


the objective of this study was to develop and investigatethe measurement properties of a single-item PtGA, to serve as avalid, reliable and responsive measure of HS-specific HRQoL


Kirby, J. S., B. Hereford, L. Thorlacius, B. Villumsen, J. R. Ingram, A. Garg, M. Butt, S. Esmann, T. King, J. Tan and G. B. E. Jemec


Journal: The British journal of dermatology
Volume: 184
Issue: 4
Pages: 681 - 687
Year: 2021
DOI: 10.1111/bjd.19344

Further Study Information

Current Stage: Completed
Funding source(s): .S.K. received funding from the Agency for Health-care Research and Quality for this research(K08HS024585). Use of REDCap through Penn State is supported by National Institutes of Health/National Center for Advancing Translational Sciences Grant Number UL1 TR000127 and UL1TR002014 through The Penn State Clinical and Translational Research Institute, Pennsylvania State University Clinical and Translational Science Award. J.R.I. received funding from Health and Care Research Wales (Health Fellowship 14-08)

Health Area

Disease Category: Skin

Disease Name: Hidradenitis Suppurativa

Target Population

Age Range: Unknown

Sex: Either

Nature of Intervention:

Stakeholders Involved

- Clinical experts
- Consumers (patients)

Study Type

- Recommendations for outcome measures (measurement/how)


- Focus group(s)
- Interview

The initial item was translated into Danish based on recognized methods for cross-cultural adaptation. Cognitive debriefing interviews and focus groups were conducted with people with HS to evaluate the item. Field testing and psychometric assessment of the item was conducted with an observational noninterventional study conductedin the USA and Denmark.