Global consensus process to establish a core data set for hidradenitis suppurativa registries

Background Several registries for hidradenitis suppurativa (HS) already exist in Europe and USA. There is currently no global consensus on a core dataset (CDS) for these registries. Creating a global HS registry is challenging due to logistical and regulatory constraints, which could limit opportunities for global collaboration due to differences in the dataset collected. The solution is to encourage all HS registries collect the same CDS of information, allowing the registries to collaborate. Objectives To establish a core set of items to be collected by all HS registries globally. The core set will cover demographic details, comorbidities, clinical examination findings, patient-reported outcome measures and treatments. Methods Beginning in September 2022 twenty participants including both clinicians with expertise in HS and patient advocates in eight countries across three continents participated in a Delphi process consisting of four rounds of voting, with all participants completing each round. A list of potential items for inclusion in the core set was generated from the relevant published literature, including systematic reviews into co-morbidities in HS, clinical and examination findings, and epidemiology. For disease severity and progression items, the HIdradentitis SuppuraTiva Core outcome set International Collaboration (HISTORIC) core set and other relevant instruments were considered for inclusion. This resulted in 47 initial items. Participants were invited to suggest additional items to include during the first round. Anonymous feedback was provided to inform each subsequent round of voting to encourage consensus. Results The eDelphi process established a CDS of 48 items recommended for inclusion in all HS registries globally. Conclusions The routine adoption of this CDS in current and future HS registries should allow registries in different parts of the world to collaborate, enabling research requiring very large numbers of participants