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'Doing exactly what it says on the tin': Does NHS Healthier You stick to behaviour change evidence?

The NHS Healthier You: NHS Diabetes Prevention Programme  is designed to help people at risk of developing diabetes. Healthier You involves people meeting in groups to get support and work out how best to make changes to their lifestyle. These courses are being delivered to thousands of people across England, by four different organisations working to a common blueprint. 

Although Healthier You is based on evidence on what works to prevent diabetes, some people have criticised the programme, suggesting it is not the best way to prevent diabetes. Lots of people are keen to see if the programme really delivers better health. 

There are many ways in which a course such as Healthier You may not work as well as planned. For example, not enough people may want to take part, or it may attract people who are not likely to really benefit. At present, it does not appear that either of these problems has occurred.  

Another potential problem is whether Healthier You is delivered with fidelity. This is a technical term which relates to whether something designed to improve health is delivered in the way it was intended. Drugs can be manufactured so that they include all the right ingredients for patients and lots of checks will be put in place to make sure that they do. When the NHS is trying to help people make changes to their lifestyle without medication, the same principles apply – but it is all much more complicated.   

Fidelity can take a number of specific forms in the NHS Healthier You course (see Box 1)

It is really important to evaluate the fidelity of courses such as Healthier You. Without checking fidelity, we cannot know if it is being delivered as it was designed to be, and we won’t be able to understand problems that might occur. For example, if people are not seeing benefit, is that because Healthier You is just not a good way of preventing diabetes – or it is just because it is not always being done as accurately as it might?

Evaluating fidelity in Healthier You

NHS England drew up a Service Specification outlining what they wanted from anyone who provided the ‘Healthier You’ course. This specification was informed by the best evidence available. 

The specification stated that ‘Healthier You’ must be delivered in line with relevant guidelines – especially National Institute of Health and Care Excellence (NICE) PH38, ‘Preventing Type 2 Diabetes: Risk identification and interventions for individuals at high risk’ (NICE, 2012).

Both the specification and NICE PH38 guideline describe how the intervention should be delivered.  For example, Healthier You needs to be delivered in person in groups of no more than 20 people, over a minimum of nine months, comprising at least 13 sessions and 16 hours of contact time.

Not only that, but these guidelines stated what strategies should be used to deliver the programme, which we can think of as the ‘active ingredients’ of the intervention. This means that they talked about particular behaviour change techniques that best help people change their lifestyle. For example, Healthier You has to tell people about the consequences of different behaviours for their health and diabetes risk, help people set goals for change, and encourage people to find others to support them to make those changes.

Organisations who wanted to deliver Healthier You submitted documents to say how they would deliver the course, and what they would deliver.  After four organisations were selected, they each developed handbooks to help their staff deliver the Healthier You course.

So how are we testing the fidelity of Healthier You?

Researchers from the DIPLOMA research programme, funded by the NIHR, are comparing the courses delivered by the four providers with the scientific evidence, and the specification for the course created by NHS England. We are looking at the documents and materials used, observing staff training, observing delivery of the programme and interviewing people who have been on the Healthier You course.

What have we found?

Our early data suggest that the courses generally included the right ingredients, delivered in the right way. However, the different courses did differ in the degree to which their strategies for helping people change their lifestyles (i.e behaviour change techniques) matched the specification. Every provider organisation included some techniques that were not specified, and no provider included every technique that was specified. Fidelity was generally very good, but there was still some room for improvement. 

Having identified these differences, we are now working with NHS England to make sure that our work informs the next wave of Healthier You programmes, to maximise the impact on preventing diabetes.


*This blog was originally published on the Collaboration for Leadership in Applied Health Research and Care (CLAHRC) Greater Manchester website.

About the authors: Elaine Cameron is Research Associate at the School of Health Sciences at The University of Manchester. David French is Professor of Health Psychology and Chair of Health Psychology at the School of Social Sciences, The University of Manchester.

The DIPLOMA study is funded by the NIHR’s Health Services and Delivery Research (HS&DR) Programme. More information on the study is available on the NIHR Journals Library.


The views and opinions expressed in this blog are those of the authors and do not necessarily reflect those of the NIHR or the Department of Health and Social Care.