Type 2 diabetes prevention and remission: the latest research
Prevention and remission of type 2 diabetes is crucial for tackling the projected increases in incidence in coming years. The logistics of setting up a large-scale programme in England and the challenges of achieving similar success elsewhere were discussed at the recent International Diabetes Federation meeting in Lisbon. Dr Susan Aldridge reports.
While the oral glucose tolerance test (OGTT) is often used to identify those at risk of type 2 diabetes, NHS England uses a two-stage approach. First, a risk assessment tool is used and then, if needed, either HbA1c or fasting blood glucose is measured. Results between 42-47 mmol/mol or 5.5-6.9 mol/l, respectively, identify a high-risk individual who would be eligible for the NHS Diabetes Prevention Programme (DPP).
There is a big evidence base for interventions to delay or prevent the onset of type 2 diabetes from Finland, India, Japan and the USA, where the OGTT is used to identify those at risk. However, recent work from England used HbA1c and found a 43% reduction in type 2 diabetes with lifestyle intervention. “We now have evidence that defining risk this way and introducing lifestyle intervention does have good randomised clinical control evidence behind it,” said Professor Jonathan Valabhji, National Clinical Director for Diabetes and Obesity at NHS England, who played a leading role in setting up the NHS Diabetes Prevention Programme (DPP).
Back in 2014, the Five Year Forward View report expressed concern about the sustainability of the NHS, placing much more emphasis upon prevention. Professor Valabhji saw an opportunity to set up a national diabetes prevention programme and it was fully supported and funded after the 2015 General Election.
Setting up the NHS DPP
Early stages of the NHS DPP saw the establishment of a reference group, a service specification and procurement of providers. The service specification was similar to the US DPP, consisting of a nine-month group-based programme with 13 sessions based around losing weight, healthy eating and increasing physical activity. After a gradual roll-out across England, full coverage was achieved by the summer of 2018. “Referral was by GPs and they are very good at targeting those most in need of these interventions,” said Professor Valabhji. “We were also able to show that our attendees adequately represented high-risk groups, such as those in more deprived areas, South Asians and Afro-Caribbeans.”
Outcomes of the NHS DPP
Data on the first 350,000 participants showed a mean weight decrease of 3.3 kg and a mean HbA1c decrease of 2.0% for completers of the programme (those who had attended 60% or more of the sessions). “This is taxpayers’ money, so there is a huge responsibility for those of us who implemented the programme to make sure it does what it says on the tin,” said Professor Valabhji. The National Institute of Health Research funded and commissioned an independent study, published at the Diabetes UK conference earlier this year, and it showed that the relative risk reduction of completers compared with those attending none of the sessions is 37%. “Even more pleasing was that the independent analysis was able to demonstrate a 7% reduction of type 2 diabetes incidence in the English population, not just attendees at the NHS DPP,” he added.
From the beginning, there was huge political pressure to deliver NHS DPP digitally. “We always said the programme would be evidence-based and, when we set it up in 2015, we didn’t think the evidence was strong enough to deliver digitally,” said Professor Valabhji.
Then a pilot study of a 12-month digital programme with peer support, a telephone service and a website was set up in nine areas with five providers and 3,500 participants. This led to significant reductions in weight and HbA1c.
Since these findings were ready by the onset of the pandemic, the NHS DPP providers were able to adapt the entire programme to digital or remote delivery and recruitment soon picked up to pre-pandemic levels after a sharp dip at the start.
In a paper on baseline weights from April 2017 to April 2021, a very rapid rise – most marked in younger people, women and those living in deprived areas – was noted at the onset of lockdown and this has still not returned to pre-pandemic baseline levels.
By early 2022, around 117,000 people had been referred to the remote programme and 25,000 to the digital programme. Average weight losses were 3.3 kg for remote and 5 kg for digital, compared with historical data of 3 kg for the original face-to-face option. It is not clear why so much more weight was lost in the digital group, who tended to be younger, but were also starting from a higher baseline weight. The digital programme is done by the participant on their own, while the remote option is done in groups (like a Zoom meeting). It may be that the digital programme is preferred by those who feel there is stigma attached to obesity and overweight, and would prefer to work alone in their weight loss, while others prefer the support of a group.
Type 2 remission on the NHS
The NHS Type 2 Diabetes Path to Remission programme was set up in 2019 and is based on evidence from the DiRECT and DROPLET studies of low-calorie diets involving total meal replacement (TMR) consisting of soups and shakes. The model of the remission programme is similar to that of the NHS DPP. Participants receive TMR for three months, followed by two months of food re-introduction, then seven months of behavioural support to maintain their weight loss.
After a six-month delay because of the pandemic, the programme was rolled out in September 2020 to 25% of England and earlier this year reached 50% of the country. NHS England is now in the process of putting providers in place for the rest of the country.
“Five thousand people have started the programme so far and we are pleased to see an excess of referrals from the most deprived areas,” said Professor Valabhji. “The most common BMI among participants is 30 to 35 and, while participants in DiRECT were mainly white, our programme includes people from different ethnic groups, with 20% Asian and 6-8% Afro-Caribbean.”
Retention rates are “very encouraging” with 56% completing the programme. And when it comes to weight loss, this is very similar to that reported in the trials at an average of 10.3% of body weight and 11.4 kg at 12 months. This data is being linked to the National Diabetes Audit, which will give HbA1c and prescription findings, enabling the rate of type 2 remission to be revealed sometime in the next six months, so watch this space.
Do prevention strategies really work?
Findings from NHS England are encouraging but what about type 2 prevention programmes elsewhere? Dr Timotheus Dorh, who recently served as Chair of IDF North America and Caribbean region, is from St Lucia and has a special interest in non-communicable diseases, such as diabetes. He has reviewed evidence from around the world to put together some ideas about what does – and does not – make an effective prevention strategy.
“We know, as scientists, that the prevention strategies can decrease the risk of diabetes,” he said. “Almost every country in the world has some form of diabetes prevention now.” But how do you determine the success of these programmes? Incidence rates of type 2 diabetes have decreased in the US between 2001 and 2019 and one could assume that this is because of the prevention programme. However, the IDF Atlas shows that prevalence and mortality have generally increased.
“I think there is really not enough data to determine the success of our strategies,” said Dr Dorh. “More than one third of countries in the world have no reliable mortality data and estimating mortality due to diabetes is also challenging. If someone dies of a complication, diabetes may not appear on the death certificate. Many people with diabetes are also living longer. So we might be looking at the wrong data. It would maybe help to look at some mixture of incidence and prevalence.”
There is also wide variability in enforcement of prevention strategies by country and, often, a lack of co-ordination in efforts. On this point, Dr Dorh noted that the Centers for Disease Control and Prevention (CDC) in the US had trained community organisations in prevention, which had increased patient support. In contrast, this approach is harder to sustain in low- and middle-income countries and, as a result, patient support can be poor, which impacts the success of the prevention strategy. Finally, there is sometimes lack of funding. “Even though the interventions themselves are cheap, the associated education costs money,” said Dr Dorh. “IDF could pay, but the onus for this is really on governments.”
Recommendations for successful prevention
Dr Dorh made a number of recommendations based on his review. First, countries should implement programmes that score highly in the PIPE impact metric. This means Penetration, which is the ability of the programme to reach the people who need it, involving scaling up. Implementation and Participation means ability to set up the programme and get people involved. And, finally, Effectiveness, which would cover weight loss, completion of the programme and, most importantly, reduction in type 2 diabetes incidence.
Furthermore, the programme should be implemented in its entirety and involve all stakeholders in planning and discussion. In many countries, health insurance is a big problem, so insurers should be approached to increase coverage. Finally, governments should invest in research and data analysis, as well as support groups run by organisations such as the IDF, and volunteers should be encouraged to work on prevention programmes.
“In conclusion, I would like to say that data analysis and collection is crucial to determine how successful current prevention strategies are,” said Dr Dorh. “Often, even when successful studies are published, there is no infrastructure available to carry out the cost-effective strategies recommended. Remember, what works in your country may not work elsewhere because of economic, social and cultural factors.”
He finished with a quote from Nelson Mandela, which could be applied to type 2 diabetes prevention work: ‘If you talk to a man in language he understands, that goes to his head. If you talk to him in his own language, that goes to his heart’.
Any opinions expressed in this article are the responsibility of the EASD e-Learning Programme Director, Dr Eleanor D Kennedy.