Background: Eustachian Tube Dysfunction (ETD) is a common condition associated with significant morbidity and middle ear pathology. While management has evolved from bypassing the tube with grommets to functional restoration via Balloon Eustachian Tuboplasty (BET), the evidence supporting these interventions remains uncertain (Swords et al., 2025). Recent systematic reviews have highlighted that primary studies utilise heterogeneous outcome measures, preventing effective meta-analysis (Raymond et al., 2022; Golota et al., 2025; Swords et al., 2025). Furthermore, diagnostic accuracy studies suggest a poor correlation between patient-reported symptoms and objective function (Smith et al., 2018, p. 201), complicating the interpretation of treatment success. This study aims to develop a standardised Core Outcome Set (COS) to ensure consistency and comparability in future clinical trials.
Methods: A systematic review will be done to identify candidate items for the COS. Subsequently, patient qualitative interviews will be conducted in the UK to generate further candidate items. An iterative consensus process by an international panel will then be undertaken to select essential outcome measures for adult & paediatric ETD. Outcome instruments will be standardised in alignment with COSMIN guidelines.
Dewei Tan,
Ju Yi Tai,
Victor Lim,
Keith Lee,
Andreas Markides,
Matthew Smith (Principal Investigator)
Disease Category: Ear, nose, & throat
Disease Name: Eustachian Tube Dysfunction
Age Range: 0 - 120
Sex: Either
Nature of Intervention: Any
- Clinical experts
- Consumers (caregivers)
- Consumers (patients)
- Researchers
- COS for clinical trials or clinical research
- Recommendations for outcome measures (measurement/how)
- Consensus meeting
- Delphi process
- Focus group(s)
- Interview
- Literature review
- Semi structured discussion
- Survey
- Systematic review
Study Protocol:
Phase 1: Candidate Item Generation
Systematic Review:
A systematic review will be conducted to extract all outcomes measures and measurement instruments previously reported in ETD trials.
Qualitative Interviews:
Semi-structured interviews will be conducted with UK-based adult ETD patients and parents of paediatric patients.
Two researchers will then independently extract the candidate items.
Taxonomy mapping:
Candidate items from both sources will be deduplicated and grouped into broad outcome domains by the Study Management Group.
Phase 2: Iterative Consensus Process (e-Delphi Survey)
An anonymous e-Delphi survey will be constructed using Google Forms, consisting of the identified outcome domains. The survey will be distributed to UK-based patients/parents and an international professional panel.
Round 1: Participants will rate the importance of candidate items on a 9-point Likert scale (1-3: limited importance; 4-6: important but not critical; 7-9: critical). Patients/Parents will score candidate outcome domains only. Professionals will score candidate outcome domains and outcome measurement instruments. Both groups may also suggest new outcomes or instruments to be added to subsequent rounds.
Round 2: Participants will be shown their Round 1 score alongside the aggregated scores of their own and other stakeholder groups. They will be asked to re-score the items.
Round 3: Participants will score any remaining items that did not reach consensus. They will be shown the aggregated scores of the patient/parent group alongside the professional group side-by-side to highlight disparities and encourage final consensus.
Consensus criteria: A predefined threshold (>70% rating 7-9 and <15% rating 1-3) will be used to determine consensus for inclusion ("IN") or exclusion ("OUT"). Items not meeting these criteria will enter the "Grey Zone".
Phase 3: Consensus Meeting & Instrument Selection
A final meeting with representative stakeholders will be held to discuss "Grey Zone" items and confirm the final core outcome domains. Following agreement on the core outcome set (COS), the COSMIN guidelines will be applied to select and standardise the specific instruments for each core outcome.