Core Outcome Set for IgE‐mediated food allergy clinical trials and observational studies of interventions: International Delphi consensus study ‘COMFA’

Background IgE‐mediated food allergy (FA) is a global health concern with substantial individual and societal implications. While diverse intervention strategies have been researched, inconsistencies in reported outcomes limit evaluations of FA treatments. To streamline evaluations and promote consistent reporting, the Core Outcome Measures for Food Allergy (COMFA) initiative aimed to establish a Core Outcome Set (COS) for FA clinical trials and observational studies of interventions. Methods The project involved a review of published clinical trials, trial protocols and qualitative literature. Outcomes found as a result of review were categorized and classified, informing a two‐round online‐modified Delphi process followed by hybrid consensus meeting to finalize the COS. Results The literature review, taxonomy mapping and iterative discussions with diverse COMFA group yielded an initial list of 39 outcomes. The iterative online and in‐person meetings reduced the list to 13 outcomes for voting in the formal Delphi process. One more outcome was added based on participant suggestions after the first Delphi round. A total of 778 participants from 52 countries participated, with 442 participating in both Delphi rounds. No outcome met a priori criteria for inclusion, and one was excluded as a result of the Delphi. Thirteen outcomes were brought to the hybrid consensus meeting as a result of Delphi and two outcomes, ‘allergic symptoms’ and ‘quality of life’ achieved consensus for inclusion as ‘core’ outcomes. Conclusion In addition to the mandatory reporting of adverse events for FA clinical trials or observational studies of interventions, allergic symptoms and quality of life should be measured as core outcomes. Future work by COMFA will define how best to measure these core outcomes. Core Outcome Measures for Food Allergy (COMFA) initiative, through international modified Delphi consensus process, has established a Core Outcome Set (COS) for IgE‐mediated food allergy measured in clinical trials and observational studies of interventions. ‘Allergic symptoms’ and ‘quality of life’ achieved consensus for inclusion in the final COS. ‘Desensitisation’ and ‘remission/sustained unresponsiveness’ were considered important but did not reach a predefined threshold for inclusion in all three stakeholder groups.Abbreviations: COMFA, Core Outcome Measures for Food Allergy COS, Core Outcome Set; IgE, immunoglobulin E.