Acute otitis externa: Consensus definition, diagnostic criteria and core outcome set development
Authors: Smith Matthew E. , Hardman John C. , Mehta Nishchay , Jones Gareth H. , Mandavia Rishi , Anderson Caroline , Khan Maha , Abdelaziz Aula , Al-Dulaimy Bakir , Amin Nikul , Anmolsingh Rajesh , Anwar Bilal , Bance Manohar , Belfield Katherine , Bhutta Mahmood , Buchanan Ruaridh , Chandrasekharan Deepak , Chu Michael , Chundu Srikanth , Conroy Katherine , Crundwell Gemma , Daniel Mat , Daniels Jessica , De Sujata , Dobbs Sian , Doshi Jayesh , Farr Matthew , Ferdous Tanjinah , Fragkouli Eleni , Freeman Simon , Ghosh Samit , Gosnell Emma , Hannan S. Alam , Heward Elliot , Javed Faisal , John Deepa , Nicholls Helen , Kasbekar Anand V. , Khan Haroon , Khan Hammad , Khwaja Sadie , Kotecha Bhik , Krishnan Madhankumar , Kumar Nirmal , Lamb Tamara , Lancer Hannah , Manjaly Joseph G. , Martinez Del Pero Marcos , McClenaghan Fiona , Milinis Kristijonas , Mistry Nina , Mohammed Hassan , Morris Elizabeth , Morris-Jones Stephen , Padee Jessica , Pal Surojit , Patel Sanjay , Pericleous Agamemnon , Qayyum Asad , Rouhani Maral , Saeed Haroon , Santhiyapillai Mirusanthan , Seymour Kay , Sharma Sunil , Siau Richard , Singh Arvind , Stapleton Emma , Stephenson Kate , Stynes Gill , Subramanian Bharathi , Summerfield Neil , Swords Chloe , Trinidade Aaron , Tse Antonia , Twumasi Emmanuel , Ubhi Harmony , Unadkat Samit , Vijendren Ananth , Wasson Joe , Watson Glen , Williams Glennis , Wilson Janet , Yao Alexander , Youssef Ahmed , Lloyd Simon K. W. , Tysome James R. ,   on behalf of INTEGRATE (The UK ENT Trainee Research Network)
Published: May 2021

Objective
Evidence for the management of acute otitis externa (AOE) is limited, with unclear diagnostic criteria and variably reported outcome measures that may not reflect key stakeholder priorities. We aimed to develop 1) a definition, 2) diagnostic criteria and 3) a core outcome set (COS) for AOE.

Study design
COS development according to Core Outcome Measures in Effectiveness Trials (COMET) methodology and parallel consensus selection of diagnostic criteria/definition.

Setting
Stakeholders from the United Kingdom.

Subjects and methods
Comprehensive literature review identified candidate items for the COS, definition and diagnostic criteria. Nine individuals with past AOE generated further patient-centred candidate items. Candidate items were rated for importance by patient and professional (ENT doctors, general practitioners, microbiologists, nurses, audiologists) stakeholders in a three-round online Delphi exercise. Consensus items were grouped to form the COS, diagnostic criteria, and definition.

Results
Candidate COS items from patients (n = 28) and literature (n = 25) were deduplicated and amalgamated to a final candidate list (n = 46). Patients emphasised quality-of-life and the impact on daily activities/work. Via the Delphi process, stakeholders agreed on 31 candidate items. The final COS covered six outcomes: pain; disease severity; impact on quality-of-life and daily activities; patient satisfaction; treatment-related outcome; and microbiology. 14 candidate diagnostic criteria were identified, 8 reaching inclusion consensus. The final definition for AOE was ‘diffuse inflammation of the ear canal skin of less than 6 weeks duration’.

Conclusion
The development and adoption of a consensus definition, diagnostic criteria and a COS will help to standardise future research in AOE, facilitating meta-analysis. Consulting former patients throughout development highlighted deficiencies in the outcomes adopted previously, in particular concerning the impact of AOE on daily life.