Diverticular Disease PSP protocol


Published: 10 April 2024

Version: 1

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Purpose of the PSP and background

The purpose of this protocol is to clearly set out the aims, objectives and commitments of the Diverticular Disease Priority Setting Partnership (PSP) in line with James Lind Alliance (JLA) principles. The Protocol is a JLA requirement and will be published on the PSP’s page of the JLA website. The Steering Group will review the Protocol regularly and any updated version will be sent to the JLA.

The JLA is a non-profit making initiative, established in 2004. It brings patients, carers and clinicians together in PSPs. These PSPs identify and prioritise the evidence uncertainties, or ‘unanswered questions’, that they agree are the most important for research in their topic area. Traditionally PSPs have focused on uncertainties about the effects of treatments, but some PSPs have chosen to broaden their scope beyond that. The aim of a PSP is to help ensure that those who fund health research are aware of what really matters to patients, carers and clinicians. The National Institute for Health and Care Research (NIHR) coordinates the infrastructure of the JLA to oversee the processes for PSPs, based at the NIHR Coordinating Centre (NIHRCC), University of Southampton.

Diverticular disease is a diagnosis given in people who have symptoms and is extremely common in the developed world. Between 1 in 3, increasing to 1 in 2 people will be affected during their lifetime (Strait et al, 2012), including the rising rates in younger people. For example, 160,775 people were admitted to hospital in the UK with diverticular disease related symptoms such as diverticulitis in 2020 (Hospital episode statistics 2019-2020: Secondary Care Analytical Team, 2020).

What does diverticular disease look like?

  • Diverticulum: A diverticulum is a small pouch about 1cm in size which sticks out from the wall of the large bowel.
  • Diverticula: This refers to more than one Diverticulum. The most common site for diverticula is on the lower part of the large bowel on the left-hand side. They are permanent unless the affected part of the bowel is surgically removed.
  • Diverticulitis: Diverticulitis means the condition that occurs when a single diverticulum or several diverticula become inflamed or infected.
  • Diverticulosis: You may have heard the term diverticulosis, which means the presence of diverticula; this is not the same as diverticular disease. Most people with diverticulosis do not have, or go on to develop, diverticular disease. The great majority of people with diverticulosis will live out their lives never having symptoms. Having symptoms is diagnosed as diverticular disease.

For a more detailed explanation of how diverticular disease’s severity of symptoms are classified, view this diagram.

What are the symptoms?

The most common symptoms of diverticular disease include:

  • Lower abdominal pain
  • Bloating (increase in abdominal size due to gas)
  • Change in bowel habit (diarrhoea or constipation)
  • Mucus or blood in the stool

The pattern of symptoms differs from one person to the next, but pain is often crampy, and it comes and goes. The pain is usually focused in the left side of the abdomen (belly) where the diverticula most often occur. However, for others, including people of South Asian origin, symptoms may occur on the right-hand side of the abdomen.

In some cases, complications can develop such as abscesses, fistulas, bowel obstructions, perforations, and large bleeds.

Why is this PSP important?

Considering how many people it affects, little research has been done into Diverticular Disease. There are many unknowns about how and why it develops and why there is increasing incidences in younger people and what are the optimal treatments. We need to identify and prioritise unanswered questions and increase our understanding of this disease.

The Diverticular Disease PSP is funded by Guts UK Charity (50%) and Bowel Research UK (50%)

Aims, objectives and scope of the PSP

The aim of the Diverticular Disease (DD) PSP is to identify the unanswered questions about Diverticular Disease from patients, carers, and healthcare professionals based in the UK to identify and then prioritise gaps in causes, diagnosis, treatment, management (including prevention), and support for people with diverticular disease.

The DD PSP covers all diverticular diseases as stated in section one (Purpose of the PSP and background).

The objectives of the PSP are to:

  • work with people affected by Diverticular Disease (patients 18+), carers and healthcare professionals to identify uncertainties about causes, diagnosis, treatment, management (including prevention, e.g. diet) and support for people with diverticular disease
  • agree by consensus a prioritised list of those uncertainties, for research
  • publicise the results of the PSP and process
  • take the results to research commissioning bodies to be considered for funding

Inclusion criteria

  • Diverticular Disease of the large bowel
  • Patients aged 18+
  • Carers/family members
  • Healthcare professionals and allied health professionals

Exclusion criteria

  • It is recognised that international participants may respond to the surveys, in which case their priorities will be separated and shared with their relevant overseas groups.
  • Any questions that are not related to diverticular disease of the large bowel will be looked at separately.

The Steering Group

The Steering Group includes membership of patients and carers and clinicians, as individuals or representatives from a relevant group.

The Diverticular Disease PSP will be led and managed by a Steering Group involving the following:

Patient and carer representative/s

  • Eric Douglin: Patient
  • Penny Flavell: Carer
  • Linda Griffiths: Patient
  • Darren Gulston: Patient/Carer
  • Lisa Hawke: Patient
  • Sophie Miller: Patient
  • Sue Hoolahan: Patient

Clinical representative/s

  • Dr Jamie Catlow: Consultant Gastroenterologist at Newcastle Hospital NHS Foundation Trust
  • Dr David Humes: Associate Professor of Surgery, University of Nottingham
  • Prof Jo Martin: Professor of Pathology, Queen Mary University London
  • Dr Jonathan Simpson: GP Registrar, County Durham
  • Mr Neil Smart: Consultant Colorectal Surgeon & Honorary Associate Professor, Exeter, UK
  • Julie Thompson: Specialist Dietitian in Gastroenterology; Information Manager at Guts UK Charity
  • Gabrielle Thorpe: Associate Professor in Colorectal & Stoma Care Nursing, University of East Anglia
  • Mr Dale Vimalachandran: Consultant Colorectal surgeon at the Countess of Chester Hospital NHS Foundation Trust
  • Prof Amanda Williams: Professor of Clinical Health Psychology, University College London

Project Team

  • Mr Dale Vimalachandran: PSP Clinical Lead
  • Helen West: PSP Lead, Guts UK Charity
  • Sam Alexandra Rose: PSP Coordinator, Bowel Research UK Charity
  • Maryrose Tarpey: James Lind Alliance Advisor and Chair of the Steering Group
  • Kristina Staley: Information Specialist

The Steering Group will agree the resources, including time and expertise that they will be able to contribute to each stage of the process, with input and advice from the JLA.


Organisations and individuals will be invited to be involved with the PSP as partners. Partners are organisations or groups who will commit to supporting the PSP, promoting the process and encouraging their represented groups or members to participate. Organisations which can reach and advocate for these groups will be invited to become involved in the PSP. Partners represent the following groups:

  • people who have or had diverticular disease
  • carers of people who have or had diverticular disease
  • health and social care professionals - with experience of dealing with patients with diverticular disease
  • Charities and other organisations that are involved in diverticular disease

Exclusion criteria

Some organisations may be judged by the JLA or the Steering Group to have conflicts of interest. These may be perceived to potentially cause unacceptable bias as a member of the Steering Group. As this is likely to affect the ultimate findings of the PSP, those organisations will not be invited to participate. It is possible, however, that interested parties may participate in a purely observational capacity when the Steering Group considers it may be helpful.

The methods the PSP will use

This section describes a schedule of proposed steps through which the PSP aims to meet its objectives. The process is iterative and dependent on the active participation and contribution of different groups. The methods used in any step will be agreed through consultation between the Steering Group members, guided by the PSP’s aims and objectives. More details of the method are in the Guidebook section of the JLA website where examples of the work of other JLA PSPs can be seen.

Step 1: Identification and invitation of potential partners

Potential partner organisations will be identified through a process of peer knowledge and consultation, through the Steering Group members’ networks. Potential partners will be contacted and informed of the establishment and aims of the Diverticular Disease PSP.

Step 2: Awareness raising

PSPs will need to raise awareness of their proposed activity among their patient, carer and clinician communities, in order to secure support and participation. Depending on budget, this may be done by a face-to-face meeting, or there may be other ways in which the process can be launched, e.g. via social media. It may be carried out as part of steps 1 and/or 3. The Steering Group should advise on when to do this. Awareness raising has several key objectives:

  • to present the proposed plan for the PSP
  • to generate support for the process
  • to encourage participation in the process
  • to initiate discussion, answer questions and address concerns.

Step 3: Identifying evidence uncertainties

The Diverticular Disease PSP will carry out a consultation to gather uncertainties from patients, carers and clinicians. A period of 12-18 months will be given to complete this exercise (which may be revised by the Steering Group if required).

The Steering Group will use the following methods to reach the target groups

  • Online and paper surveys
  • Less heard from communities, visiting, posters with QR codes + Phone Number + Website

Existing sources of evidence uncertainties may also be searched.

Step 4: Refining questions and uncertainties

The consultation process will produce ‘raw’ questions and comments indicating patients’, carers and clinicians’ areas of uncertainty. These raw questions will be categorised and refined by Kristina Staley, Information Specialist into summary themed questions which are clear, addressable by research, and understandable to all. Similar or duplicate questions will be combined where appropriate. Out-of-scope and ‘answered’ submissions will be compiled separately. The Steering Group will have oversight of this process to ensure that the raw data is being interpreted appropriately and that the summary questions are being worded in a way that is understandable to all audiences. The JLA Adviser will observe to ensure accountability and transparency.

This will result in a long list of in-scope summary questions. These are not research questions and to try and word them as such may make them too technical for a non-research audience. They will be framed as researchable questions that capture the themes and topics that people have suggested.

The summary questions will then be checked against evidence to determine whether they have already been answered by research. This will be done by Kristina Staley, Information Specialist. The PSP will complete the JLA Question Verification Form, which clearly describes the process used to verify the uncertainty of the questions, before starting prioritisation. The Question Verification Form includes details of the types and sources of evidence used to check uncertainty. The Question Verification Form should be published on the JLA website as soon as it has been agreed to enable researchers and other stakeholders to understand how the PSP has decided that its questions are unanswered, and any limitations of this.

Questions that are not adequately addressed by previous research will be collated and recorded on a standard JLA template by Kristina Staley, Information Specialist. This will show the checking undertaken to make sure that the uncertainties have not already been answered. The data should be submitted to the JLA for publication on its website on completion of the priority setting exercise, taking into account any changes made at the final workshop, in order to ensure that PSP results are publicly available.

The Steering Group will also consider how it will deal with submitted questions that have been answered, and questions that are out of scope.

Step 5: Prioritisation – interim and final stages

The aim of the final stage of the priority setting process is to prioritise through consensus the identified uncertainties about Diverticular Disease. This will involve input from patients, carers and clinicians. The JLA encourages PSPs to involve as wide a range of people as possible, including those who did and did not contribute to the first consultation. There are usually two stages of prioritisation.

  1. Interim prioritisation is the stage where the long list of questions is reduced to a shorter list that can be taken to the final priority setting workshop. This is aimed at a wide audience, and is done using similar methods to the first consultation. With the JLA’s guidance, the Steering Group will agree the method and consider how best to reach and engage patients, carers and clinicians in the process. The most highly ranked questions (around 25) will be taken to a final priority setting workshop. Where the interim prioritisation does not produce a clear ranking or cut off point, the Steering Group will decide which questions are taken forwards to the final prioritisation.

  2. The final priority setting stage is generally a one-day workshop facilitated by the JLA. With guidance from the JLA and input from the Steering Group, up to 30 patients, carers and clinicians will be recruited to participate in a day of discussion and ranking, to determine the top 10 questions for research. All participants will declare their interests. The Steering Group will advise on any adaptations needed to ensure that the process is inclusive and accessible.

Dissemination of results

The Steering Group will identify audiences with which it wants to engage when disseminating the results of the priority setting process, such as researchers, funders and the patient and clinical communities. They will need to determine how best to communicate the results and who will take responsibility for this. Previous PSPs’ outputs have included academic papers, lay reports, infographics, conference presentations and videos for social media.

It should be noted that the priorities are not worded as research questions. The Steering Group should discuss how they will work with researchers and funders to establish how to address the priorities and to work out what the research questions are that will address the issues that people have prioritised. The dissemination of the results of the PSP will be led by Guts UK Charity and Bowel Research UK.

The JLA encourages PSPs to report back about any activities that have come about because of the PSP, including funded research. Please send any details to the JLA.

Agreement of the Steering Group

The Diverticular Disease PSP Steering Group agreed the content and direction of this Protocol on 21st March 2024.