A core domain set for hidradenitis suppurativa trial outcomes: an international Delphi process

Background: There is no consensus on core outcome domains for hidradenitis suppurativa (HS). Heterogeneous outcome measure instruments in clinical trials likely leads to outcome-reporting bias and limits the ability to synthesize evidence. Objectives: To achieve global multistakeholder consensus on a core outcome set (COS) of domains regarding what to measure in clinical trials for HS. Methods: Six stakeholder groups participated in a Delphi process that included five anonymous e-Delphi rounds and four face-to-face consensus meetings to reach consensus on the final COS. The aim was for a 1 : 1 ratio of patients to healthcare professionals (HCPs). Results: A total of 41 patients and 52 HCPs from 19 countries in four continents participated in the consensus process, which yielded a final COS that included five domains: pain, physical signs, HS-specific quality of life, global assessment and progression of course. A sixth domain, symptoms, was highly supported by patients and not by HCPs but is recommended for the core domain set. Conclusions: Routine adoption of the COS in future HS trials should ensure that core outcomes of importance to both patients and HCPs are collected.