People at high risk of type 2 diabetes, who attend all three sessions of a diabetes prevention programme, are about 88% less likely to get diabetes than those who received leaflets only. But the people at highest risk may also be those least likely to start or complete the programme. If confirmed in practice, the programme could delay diabetes in about 4% of those who attend all sessions.
This study looks back to reassess data from a large NIHR trial in the UK. The study aims to see whether success is linked to the level of adherence to the programme. The original study found no reduction in type 2 diabetes when considering all 880 people from 44 GP practices. Practices were randomised and either delivered three lifestyle education sessions over three years or gave patients a diabetes education leaflet.
Programmes such as the NHS Diabetes Prevention Programme, currently being rolled out, will need to carefully consider how to recruit and retain people, especially from the highest risk groups.
Why was this study needed?
An estimated 5 million people in the UK are at high risk of diabetes, which is a costly disease to treat. While high-intensity lifestyle programmes can reduce the chance of developing diabetes for those at high risk, the difficulty is in doing this cheaply for a real-world population who may be less motivated than those in clinical trials.
The Let’s Prevent Diabetes trial found that, looking at all the people at high risk of diabetes who were invited to attend three diabetes lifestyle education sessions, they were as likely to progress to diabetes as people who were given usual care (a booklet about diabetes and lifestyle). The education sessions consisted of six hours at baseline, with two three-hour sessions after 12 and 24 months.
This study reanalysed the data to see whether there was a difference between people who did and did not attend the allocated sessions. Researchers also wanted to learn more about those who didn’t attend one or all sessions, to find out if they could be targeted better.
What did this study do?
The researchers used data from a cluster randomised controlled trial first published in 2016, the Let’s Prevent Diabetes Trial. This was a large trial of 44 practices including 880 participants. This new study focused on the 447 people who were offered the education intervention, and looked to see whether their level of attendance was linked to their chances of getting diabetes during the three years of the trial.
They compared the results for different levels of attendance to the results of 443 people in the control arm of the trial, who were given educational leaflets. They also analysed common factors among people with different levels of attendance.
The original study was large enough to compare the two groups as a whole – those invited to attend versus those given a booklet. This reanalysis of sub-groups looks at associations in smaller numbers of people and is only able to give an indication of which factors may be relevant. We can’t say for sure from this observational study whether attending education sessions caused the lowered chances of diabetes. The researchers carefully controlled for other factors, such as obesity, that might have also been linked to this effect.
What did it find?
- The first education session was attended by 77.4% of those invited (346 out of 447 people), 55.5% (248 participants) attended the first session and one refresher session, but only 29.1% (130 participants) attended all three sessions.
- People were less likely to attend one or more sessions if they were younger, smoked, had a higher body mass index and were female or from deprived areas.
- People who attended two sessions were 62% less likely to get diabetes during the 3-year study compared to people given usual care (hazard ratio (HR) 0.38, 95% confidence interval (CI) 0.24 to 0.62). People who attended all three sessions were 88% less likely to get diabetes (HR 0.12, 95% CI 0.05 to 0.28). These results did not change with adjustment for age, sex, deprivation score, smoking status or body mass index.
- Looking at all people who were invited for lifestyle sessions, there were 57.6 cases of diabetes for every 1000 people per year. For those who attended all sessions, that fell to 16.8 cases for every 1000 people per year. This suggests that about 4 people in every 100 benefit from attending all sessions or that 25 people need to be enrolled and attend three sessions for one to benefit over a year.
What does current guidance say on this issue?
NICE recommends identifying people at high risk of developing diabetes through a risk assessment score and blood test. It says people identified as high risk should be provided with “a quality-assured, evidence-based, intensive lifestyle-change programme to prevent or delay the onset of type 2 diabetes.”
These programmes should target groups of 10 to 12 people, meet eight times over a period of 9 to 18 months and deliver 16 hours of contact time, the guideline says. This is more time than the Let’s Prevent Diabetes programme offered (three meetings over three years, 12 hours of contact time).
The National Diabetes Prevention Programme, currently being rolled out across England, follows the guidance given by NICE. This national programme drew on NIHR funded Let’s Prevent study, which is summarised in the NIHR Dissemination Centre themed review on preventing type 2 diabetes.
What are the implications?
The study suggests group diabetes lifestyle prevention programmes may work for those who attend the sessions. The key challenge will be to engage and retain high risk people.
Younger people may be deterred by sessions that take place during the working day. Sessions could be offered outside of working hours, or at workplaces, to minimise inconvenience. However, this may make them harder to organise.
Only 19% of people invited to take part in the original study consented, which suggests that numbers willing to participate may be rather low. The results seen in clinical studies tend to be better than those seen in the real world.
Citation and Funding
Gray L, Yates T, Troughton J, et al; The Let’s Prevent Diabetes Team. Engagement, retention, and progression to type 2 diabetes: a retrospective analysis of the cluster-randomised "Let's Prevent Diabetes" trial. PLoS Med. 2016;13(7):e1002078.
This further analysis was carried out on research funded by the NIHR through the Let’s Prevent trial reported in 2016.
Davies MJ, Gray LJ, Troughton J, et al. A community based primary prevention programme for type 2 diabetes integrating identification and lifestyle intervention for prevention: the Let's Prevent Diabetes cluster randomised controlled trial. Prev Med. 2015;84:48–56.
Davies MJ, Gray LJ, Ahrabian D, et al. A community-based primary prevention programme for type 2 diabetes mellitus integrating identification and lifestyle intervention for prevention: a cluster randomised controlled trial. Programme Grants Appl Res. 2017;5(2).
NHS England. NHS Diabetes Prevention Programme. London; 2015.
NICE. Type 2 diabetes: prevention in people at high risk. PH38. London: National Institute for Health and Care Excellence; 2012.
NIHR themed review. On the level. Evidence for action on type 2 diabetes. Southampton: National Institute for Health Research; 2016.
Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre