Despite anatomical correction, people born with oesophageal atresia±tracheoesophageal fistula (OA-TOF) experience lifelong morbidity. Core outcome sets (COSs) are recognised as a means of improving research quality and, as a consequence, improving patient outcomes; one was not available for this population.

The scope of the study was to develop a COS for people born with OA-TOF that would be applicable regardless of age or geographic location.

Patient input was paramount to this study. For long-list generation, in addition to the systematic review (SR), patients and representatives were invited to participate in focus groups, interviews or complete activity packs to ascertain outcomes that matter most to them. International consensus was then sought using a two-step Delphi survey followed by an online consensus meeting.

Eight outcomes were identified through patient events that had not been picked up from SR. 175 people completed the Delphi survey from 26 countries and health care professionals from 13 different disciplines. 24 outcomes met predefined criteria for inclusion and following discussion and voting in the consensus meeting, and 14/24 outcomes were agreed for inclusion in the COS.

14 outcomes have been agreed on to form the COS. 12 of these outcomes are relevant to people of all ages, 1 to paediatric population and 1 to adult cohorts. The COS is, therefore, truly applicable lifelong, which was the scope of the project. This COS will help reduce research heterogeneity, enabling better quality research outcomes and more comparable data.