title: Protocol for the development of a core domain set for hidradenitis suppurativa trial outcomes.
abstract: Randomised controlled trials (RCTs) should have well-defined primary and secondary outcomes to answer questions generated by the main hypotheses. However, for the chronic, inflammatory skin disease hidradenitis suppurativa (HS), the reported outcome measures are numerous and diverse. A recent systematic review found a total of 30 outcome measure instruments in 12 RCTs. This use of a broad range of outcome measures can increase difficulties in interpretation and comparison of results and may potentially obstruct appropriate evidence synthesis by causing reporting bias. One strategy for dealing with these problems is to develop a core outcome set (COS). A COS is a list of outcomes that are meant as mandatory and should be measured and reported in all clinical trials. The aim of this study is to develop a COS for the management of HS.
  
  
  
  An international steering group of researchers, clinicians and a patient research partner will guide the COS development. 6 stakeholder groups are involved: patients, dermatologists, surgeons, nurses, industry representatives and drug regulatory authorities. A 1:1 ratio of patients:healthcare professionals is aimed for. The initial list of candidate items will be obtained by combining three data sets: (1) a systematic review of the literature, (2) US and Danish qualitative interview studies involving patients with HS and (3) an online healthcare professional (HCP) item generation survey. To reach consensus on the COS, 4 anonymous online Delphi rounds are then planned together with 2 face-to-face consensus meetings (1 in Europe and 1 in the USA) to ensure global representation.
  
  
  
  The study will be performed according to the Helsinki declaration. All results from the study, including inconclusive or negative results, will be published in peer-reviewed indexed journals. The study will involve different stakeholder groups to ensure that the developed COS will be suitable and well accepted.
authors.affiliation: Department of Dermatology, Zealand University Hospital, Roskilde, Denmark.|Health Sciences Faculty, University of Copenhagen, Copenhagen, Denmark.|Musculoskeletal Statistics Unit, The Parker Institute, Bispebjerg and Frederiksberg Hospital, The Capital Region of Denmark, Copenhagen, Denmark.
authors.forename: Linnea
authors.initials: L
authors.lastname: Thorlacius
authors.affiliation: Department of Dermatology & Wound Healing, Institute of Infection & Immunity, Cardiff University, Cardiff, UK.
authors.forename: John R
authors.identifier: 0000-0002-5257-1142
authors.initials: JR
authors.lastname: Ingram
authors.affiliation: Department of Dermatology, Hofstra Northwell School of Medicine, New York, New York, USA.
authors.forename: Amit
authors.initials: A
authors.lastname: Garg
authors.affiliation: The Patients' Association HS Denmark, Copenhagen, Denmark.
authors.forename: Bente
authors.initials: B
authors.lastname: Villumsen
authors.affiliation: Department of Dermatology, Zealand University Hospital, Roskilde, Denmark.|Health Sciences Faculty, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Solveig
authors.initials: S
authors.lastname: Esmann
authors.affiliation: Department of Dermatology, Penn State Hershey Medical Center, Hershey, Pennsylvania, USA.
authors.forename: Joslyn S
authors.initials: JS
authors.lastname: Kirby
authors.affiliation: Department of Dermatology, New York Medical College, Valhalla, New York, USA.
authors.forename: Alice B
authors.initials: AB
authors.lastname: Gottlieb
authors.affiliation: Harvard Medical School, Boston, Massachusetts, USA.|Department of Dermatology and Department of Medicine, Division of Rheumatology, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Merola
authors.affiliation: Dermatology Service, US Department of Veteran Affairs Medical Centre, Denver, Colorado, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Dellavalle
authors.affiliation: Musculoskeletal Statistics Unit, The Parker Institute, Bispebjerg and Frederiksberg Hospital, The Capital Region of Denmark, Copenhagen, Denmark.
authors.forename: Robin
authors.identifier: 0000-0002-6600-0631
authors.initials: R
authors.lastname: Christensen
authors.affiliation: Department of Dermatology, Zealand University Hospital, Roskilde, Denmark.|Health Sciences Faculty, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Gregor B E
authors.initials: GB
authors.lastname: Jemec
mesh_terms: D032921:Consensus; D003697:Delphi Technique; D017497:Hidradenitis Suppurativa / Q000628:therapy*; D006801:Humans; D036301:Qualitative Research; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D000078202:Systematic Reviews as Topic; D016896:Treatment Outcome
keywords: Consensus study; Core Domain Set; Core Outcome Set; Delphi study; Hidradenitis suppurativa