Consensus on the criteria needed for creating a rare-disease patient registry. A Delphi study

Patient registries (PRs) are important tools for public-health surveillance and rare-disease research. The purpose of this study is to identify the most important criteria for the creation of a rare-disease PR that could be used by public-health authorities to develop health policies.A consensus-development Delphi study was used, with participants selected for their expertize in rare diseases and registries. Participants were asked to complete a questionnaire on the most important criteria for creating PRs. Three rounds were performed.Agreement was reached on half the questions in the first round and on 89% of questions in the final round, with a total expert participation rate of around 60% by the final stage. This study made it possible to reach a broader consensus starting from experts' initial assessment of the features that should be considered for the creation of a rare-disease PR.The consensus method used made it possible to define the characteristics of a PR based on expert opinion within a rare-disease framework. This study may serve as a guide for helping other researchers plan and build a rare-disease PR.