External Validation of the IHS4-55 in a European Antibiotic-Treated Hidradenitis Suppurativa Cohort

Research output: Contribution to journalJournal articleResearchpeer-review

  • Kelsey R. Van Straalen
  • Thrasyvoulos Tzellos
  • Afsaneh Alavi
  • Farida Benhadou
  • Carlos Cuenca-Barrales
  • Mathilde Daxhelet
  • Mathieu Daoud
  • Ourania Efthymiou
  • Evangelos J. Giamarellos-Bourboulis
  • Philippe Guillem
  • Wayne Gulliver
  • Alexander Katoulis
  • Anke Koenig
  • Elizabeth Lazaridou
  • Michelle A. Lowes
  • Angelo V. Marzano
  • Lukasz Matusiak
  • Alejandro Molina-Leyva
  • Chiara Moltrasio
  • Andreas Pinter
  • Concetta Potenza
  • Errol P. Prens
  • Jorge Romaní
  • Christopher Sayed
  • Nevena Skroza
  • Dimitra Stergianou
  • Jacek C. Szepietowski
  • Anastasia Trigoni
  • Eva Vilarrasa
  • Athanassios Kyrgidis
  • Christos C. Zouboulis
  • Hessel H. Van Der Zee

Background: Previously, a new dichotomous outcome was developed, calculated as 55% reduction in the International Hidradenitis Suppurativa 4 (IHS4-55) score. It was validated in datasets of adalimumab and placebo-treated HS patients. External validation is an important aspect of clinical outcomes. Objectives: We aimed to externally validate the novel dichotomous IHS4-55 in a non-biologic treated dataset of HS patients. Methods: Data from a previously published European-wide prospective clinical study of antibiotic treatment of HS patients were used to assess the association of IHS4-55 achievement with individual reduction in inflammatory nodules, abscesses, and draining tunnels. Moreover, the associations between IHS4-55 positivity and achievement of the minimal clinically important differences (MCIDs) for Dermatology Life Quality Index (DLQI), Numerical Rating Scale (NRS) Pain, and NRS Pruritus were analyzed. Results: Data were obtained from 283 individual patients, of which 36.4% (103/283) were treated with clindamycin and rifampicin and 63.6% (180/283) with tetracyclines for 12 weeks. Achievers of the IHS4-55 demonstrated a significant reduction the counts of inflammatory nodules, abscesses, and draining tunnels (all p < 0.001). Additionally, IHS4-55 achievers had an odds ratio for achieving the MCID of DLQI, NRS Pain, and NRS Pruritus of 2.16 (95% CI 1.28-3.65, p < 0.01), 1.79 (95% CI 1.10-2.91, p < 0.05), and 1.95 (95% CI 1.18-3.22, p < 0.01), respectively. Conclusions: This study shows the external validity of the novel IHS4-55 by demonstrating a significant association between IHS4-55 achievement and a reduction in inflammatory lesion counts as well as achievement of MCIDs for DLQI, NRS Pain, and NRS Pruritus in an antibiotic-treated cohort. These findings support the use of the IHS4-55 as a novel primary outcome measure in clinical trials.

Original languageEnglish
Issue number3
Pages (from-to)362-367
Number of pages6
Publication statusPublished - 2023

Bibliographical note

Publisher Copyright:
© 2023 Authors. All rights reserved.

    Research areas

  • Clinicalrial, Endpoint, Hidradenitissuppurativa, International Hidradenitis Suppurativa 4, Outcome, Treatment, Validation

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