Protocol for the development of a global core outcome set for treatment of uncomplicated appendicitis in children

Appendicitis is a common gastro-intestinal disease, with the highest incidence between 10 and 19 years. There have been many developments in the treatment of appendicitis in children, with the most recent being the non-operative treatment for acute uncomplicated appendicitis. As demonstrated by Hall et al. in 2015, a wide variety of outcome measures have been reported in RCTs and meta-analyses regarding the treatment of appendicitis. We aim to reach a global consensus among patients, parents, researchers and physicians on the minimal set of core outcomes that should be reported in all future clinical trials investigating the surgical and non-operative treatment of acute uncomplicated appendicitis in children.



Knaapen M, MD1
Hall NJ, MD, PhD2
Van der Lee JH, MD, PhD3
Offringa, M4
van Heurn LWE, MD, PhD1
Bakx R, MD, PhD1
Gorter RR, MD, PhD1 (principal investigator)
+ On behalf of the paediatric appendicitis COS development group

1. Paediatric Surgical Centre of Amsterdam. Emma Children’s Hospital AMC & VU University Medical Centre. PO Box 22660, 1100DD Amsterdam, the Netherlands. Email: / e.vanheurn@amc.uva.n / /

2. University Surgery Unit, Faculty of Medicine, University of Southampton, Southampton General Hospital, Mailpoint 816, Tremona Rd, Southampton SO16 6YD, UK; Department of Paediatric Surgery and Urology, Southampton Children's Hospital, Southampton, UK. Electronic address:

3. Division Woman and Child, Academic Medical Centre. Meibergdreef 9, 1105AZ Amsterdam, the Netherlands. Email:

4. Child Health Evaluative Sciences, The Hospital for Sick Children, Toronto, Canada; University of Toronto, Faculty of Medicine, Toronto, Canada.

Further Study Information

Current Stage: Ongoing
Date: March 2018 - 2019
Funding source(s): None

Health Area

Disease Category: Gastroenterology

Disease Name: Acute Appendicitis

Target Population

Age Range: 0 - 18

Sex: Either

Nature of Intervention: Non-surgical, Operative and non-operative management, Surgery

Stakeholders Involved

- Clinical experts
- Consumers (caregivers)
- Consumers (patients)
- Families
- Researchers

Study Type

- COS for clinical trials or clinical research


- Consensus meeting
- Delphi process
- Literature review
- Survey
- Systematic review

To identify additional reported outcomes measures since April 2014 the existing systematic review will be updated.
A global 3-step online Delphi study will be performed to identify a set of core outcomes; to this aim, we will use the list of outcomes found in the systematic review as an initial list. Patient, parents and (paediatric) surgeons from all countries currently active in conducting clinical trials of the treatment of acute uncomplicated in children will be invited; we will invite 20 patients, 20 parents and 40 (paediatric) surgeons) per country.
After the final Delphi round, we will organise a face-to-face discussion to ratify a pragmatic and well defined core outcome set. Through purposeful sampling, representatives from all stakeholder groups will be invited, including physicians, researchers and children/parent representatives, journal editors and healthcare commissioners.
The aim of the project is to generate a pragmatic and globally acceptable core outcome set. Only outcomes for which reasonable consensus is reached internationally will be selected. Final reporting will categorized according to the 5 core areas (OMERACT FILTER 2.0 + Resource use).