Title: Evaluating the NHS Diabetes Prevention Programme (NHS DPP): the DIPLOMA research programme (Diabetes Prevention – Long term Multimethod Assessment)
Funder: Department of Health and Social Care

Abstract: The NHS Diabetes Prevention Programme (NHS DPP) is an ambitious programme to deliver an evidence-based behavioural change intervention (‘the NHS DPP intervention’) to patients at risk of developing diabetes, to encourage behaviour change and reduce risk of diabetes. The size of the programme and the complexity of its implementation present significant challenges for any evaluation. The DIPLOMA research programme is a mixed methods study delivered by an experienced multidisciplinary team, which is designed to provide (a) feedback to NHS DPP stakeholders on the delivery and outcomes of the programme to support ongoing development and quality improvement (b) a rigorous longer-term assessment of the success of the NHS DPP in meeting the aim of reducing diabetes prevalence in a way that is cost-effective and sustainable. We have the necessary skills and experience to deliver this evaluation. Our expertise includes quasi-experimental evaluations of population health initiatives, use of routine datasets to support evaluation of policy, mixed methods evaluation of regional and national policy, design and evaluation of behaviour change interventions, implementation science expertise as well as experience of the evaluation of relevant local diabetes prevention schemes. The DIPLOMA research programme will have 8 work packages: Work package 1 Access and equity will use quantitative analysis of routine data to explore the characteristics of patients who enter the NHS DPP, and those who are eligible and do not enter. This analysis will be complemented by qualitative research on the process of accessing the NHS DPP, and the experience of patients and professionals. Work package 2 Implementation will explore the process of implementation of the NHS DPP in selected sites, exploring the local organisation of the programme, workforce, funding, and pathways. Work package 3 Service Delivery and Fidelity will analyse data on uptake and adherence to the NHS DPP intervention, combined with a detailed analysis of the degree to which providers adhere to the specification for the intervention. Work package 4 Outcomes will use data collected by the NHS DPP to assess effects on patient outcomes within the programme. Data will also be linked to data from Implementation and Service Delivery and Fidelity work packages to explore factors influencing outcomes and ‘active ingredients.’ Work package 5 Comparative Effectiveness will use quantitative analysis of routine data to explore whether the NHS DPP leads to a reduction in the prevalence of diabetes and other outcomes, using suitable comparators with and without access to the NHS DPP. Work package 6 Validation sample will use a survey to evaluate the risk of confounding and allow adjustment in other work packages. Work package 7 Comparative Long Term Cost Effectiveness will use data from other work packages and external sources to create an economic model to assess the longer-term benefits in terms of improvements in quality of life, mortality and reductions in long-term care use Work package 8 Programme management will include management of the programme, co-ordination of the research work packages, liaison with stakeholders and dissemination of findings to internal (NHS DPP) and external academic, service and patient audiences.

Lay abstract: Background Type 2 diabetes is a common health condition that can cause serious health problems and reduce people’s quality of life, as well as costing a lot of money to treat. Some people are at higher risk of diabetes, and can be identified with a blood test. If people at risk make changes to their lifestyle (more exercise, losing weight), they can substantially reduce their chances of getting type 2 diabetes. The NHS and Diabetes UK are introducing a new scheme called Healthier You: the NHS Diabetes Prevention Programme (NHS DPP). People in England who are at risk of type 2 diabetes will be offered a practical course which will help them change their lifestyle. The aim is that this course will improve peoples’ health and reduce their diabetes risk. The people introducing the NHS DPP need to know if it really works to prevent diabetes and whether it is a good use of NHS resources. We have designed a project which will help answer these questions. Research plan We will look at data from the NHS DPP and from other sources, to see what types of patients are invited onto the course. We will also talk to patients and NHS professionals to understand how people are invited, and whether different ways of inviting people help or hinder certain people from attending. We will use this data to see if the NHS DPP is being used by those who need it most. We will talk to NHS clinical staff and managers responsible for the NHS DPP programme throughout England. We will ask them how they set up the service, what issues they believe help and hinder the programme, and whether they consulted with patients and their carers. We will watch as the NHS DPP is delivered to patients at risk of diabetes. We will check to see if it is done well, and what might be improved. We will look at data collected by the NHS DPP to see if registered patients finish the course and show good outcomes, such as healthy levels of blood sugar, feeling more confident about their health and losing weight. We will make sure we feed all this information back to the people running the NHS DPP so they can make improvements as they go along. The biggest challenge we face is testing whether this new NHS DPP is better at preventing type 2 diabetes than what the NHS currently does, and whether it is a good use of scarce NHS funds. To test this, we will use data that the NHS already collects in GP medical records. First, we will see if there are fewer cases of diabetes in these records after the NHS DPP is introduced, compared to the number of cases before. Then we will compare patients who were offered the course, with patients who are similar, but did not use the course. This will let us judge if the DPP is really preventing diabetes. Finally, we will take all the data we have collected and data from other research and develop what is called an ‘economic model,’ to determine what potential costs savings and benefits the NHS DPP might bring to the NHS over the longer term. Benefits Our team has the necessary skills and experience to do this. We have done similar work in the past on other national programmes. The research will benefit patients by testing whether the NHS DPP is effective, and providing information to improve the service. A Research Advisory Group (with 3 patients with experience of diabetes alongside clinical experts) will play an important role in helping us to identify the benefits to patients and the NHS.

Research activity codes: 8.1 ORGANISATION AND DELIVERY OF SERVICES
Health categories: METABOLIC AND ENDOCRINE