Publication – 2023 Jan.

Authors

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 0, Wayne Gulliver, Gregor B E Jemec, Alexander Katoulis, Anke Koenig, Elizabeth Lazaridou, Michelle A Lowes, Angelo V Marzano, Lukasz Matusiak, Alejandro Molina-Leyva, Chiara Moltrasio, Andreas Pinter, Concetta Potenza 0, Errol P Prens, Jorge Romaní, Ditte M Saunte, Christopher Sayed, Nevena Skroza 0, Dimitra Stergianou, Jacek C Szepietowski, Anastasia Trigoni, Eva Vilarrasa, Athanassios Kyrgidis, Christos C Zouboulis, Hessel H van der Zee

Abstract

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.

Keywords: Clinical trial; Endpoint; Hidradenitis suppurativa; International Hidradenitis Suppurativa 4; Outcome; Treatment; Validation.