In people at high risk of type 2 diabetes, the educational programme ‘Let’s prevent’ had minimal impact on blood sugar control, and cholesterol. Overall it did not prevent people developing diabetes, though the risk was reduced for the 29% of people who attended all three sessions.
The NIHR-funded trial compared three educational sessions plus telephone support with usual care. The main difficulty was recruitment and attendance. Only 19% of people at high risk of type 2 diabetes were willing to have a blood sugar test. Even when this showed high sugar levels, 23% of people allocated to the ‘Let’s prevent’ arm did not attend the first session.
Other programmes – with more sessions over a longer period of time – have had a greater impact. The NHS is implementing a Diabetes Prevention Programme, involving 13 personalised education and exercise sessions over nine months.
This trial highlights that focusing on maximising attendance will be vital to the success of this initiative.
Why was this study needed?
There are 2.7 million people diagnosed with type 2 diabetes in the UK. People with type 2 diabetes either do not produce enough insulin or their body does not respond to insulin, leading to high levels of glucose in the blood. If uncontrolled this can affect the circulation and increase the risk of cardiovascular disease, as well as damaging small blood vessels in organs such as the eyes and kidneys. People who have problems regulating blood sugar but have not yet reached criteria for type 2 diabetes are defined as having non-diabetic high blood sugar (hyperglycaemia), sometimes referred to as pre-diabetes. It is estimated there may be five million people who have non-diabetic hyperglycaemia.
Lifestyle changes – such as balanced diet, exercise, maintaining a healthy weight, stopping smoking, and drinking alcohol in moderation – can reduce the risk of people with non-diabetic hyperglycaemia developing type 2 diabetes. The challenge is in designing educational and exercise interventions to engage and support people in making these lifestyle changes.
What did this study do?
The first phase created and tested a software screening tool to identify people at high risk of diabetes from 44 general practices in Leicestershire. Of 17,972 identified to be at risk, 19% agreed to attend screening by glucose tolerance test. One quarter (880 people) were found to have non-diabetic hyperglycaemia. They were included in phase two, a randomised controlled trial, in which they were assigned to either usual care, including an information booklet and advice from their GP or practice nurse, or to a structured educational programme.
The ‘Let’s Prevent’ programme comprised one full day (six hours) and two half day (three hour) sessions at 12 and 24 months. Participants also received telephone calls from nursing staff every three months to offer support and encouragement. The programme was made accessible to minority ethnic groups because Leicestershire has a high proportion of people with South Indian origin, who have an increased risk of diabetes.
There were some differences in characteristics between groups, including socioeconomics, smoking status and BMI which may affect outcomes. Only 29% of people attended all face-to-face educational sessions.
What did it find?
- The ‘Let’s Prevent’ programme did not have a statistically significant effect on the main outcome of prevention of type 2 diabetes over three years (hazard ratio [HR] 0.74, 95% confidence interval [CI] 0.48 to 1.14). Type 2 diabetes developed in 14.3% compared with 15.5% of the usual care group. The number of sessions attended influenced the effectiveness of the intervention. The 248 people who attended at least two sessions had a 62% reduction in incidence, whereas the 130 people who attended all sessions had an 88% reduction compared to usual care.
- The intervention marginally reduced HbA1c (a long term measure of blood glucose control) by 0.06% compared with people receiving usual care (95% CI ‑0.11% to ‑0.01%) and low density lipoprotein cholesterol by ‑0.08 mmol/l (95% CI ‑0.15 to ‑0.01) but had no effect on total cholesterol or high density lipoprotein cholesterol.
- There was no difference in 10-year cardiovascular risk between the intervention and the usual care groups.
- There was little to no difference in self-reported diet or physical activity between groups. However, people receiving the intervention increased the amount of unsaturated fat they consumed, reduced daily sedentary time by 30 minutes, and increased their daily number of steps by 450 to 600 compared to usual care.
What does current guidance say on this issue?
NICE guidelines recommend that a validated type 2 diabetes risk assessment is performed for eligible adults aged 40 and over, those aged 25 to 39 from high-risk black and minority ethnic groups, and others with conditions that may increase their risk. People with high risk scores should receive blood tests to check fasting blood glucose.
Subsequent recommendations depend on the level of risk. These range from informing low risk individuals about lifestyle changes and appropriate services; discussing specific risk factors and local services such as structured weight-loss programmes for those at moderate risk; and referring high risk people to an intensive lifestyle-change programme.
What are the implications?
The two phases of this research indicate the difficulty in engaging people at high risk of type 2 diabetes in prevention strategies. Previous research had shown that more intensive interventions are effective, and this study seems to support that as the more sessions people attended, the less likely they were to develop type 2 diabetes.
The Healthier You: NHS Diabetes Prevention Programme includes 13 highly personalised sessions. They provide education on healthy eating and lifestyle, support to lose weight and a tailored exercise programme.
Hopefully this more intensive and individualised programme will prove more effective. However, future studies may want to focus on exploring factors behind compliance and increasing attendance to improve effectiveness.
Citation and Funding
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).
This project was funded by the National Institute for Health Research Programme Grants for Applied Research (project number RP-PG-0606-1272).
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NICE. Type 2 diabetes: prevention in people at high risk. PH38. London: National Institute for Health and Care Excellence; 2012.
PHE. Prevalence estimates of non-diabetic hyperglycaemia by local authority. London: Public Health England; 2015.
Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre