Introduction

Type 2 diabetes occurs when the body no longer produces enough insulin to regulate blood glucose levels or has developed resistance to the insulin that is produced. Owing to recent scientific breakthroughs,^1,2 type 2 diabetes is no longer seen as a progressive and irreversible disease. We now know that prevention and remission are possible with clinically effective interventions, notably weight loss. This provides a powerful tool to address the rising trajectory of type 2 diabetes incidence and related ill health in Scotland. Remission of type 2 diabetes is only one aspect; prevention will reduce the number of people in Scotland developing the condition in the first place.

The number of people being diagnosed with type 2 diabetes is increasing every year. Currently, there are almost 300,000 people living in Scotland with type 2 diabetes, with new diagnoses in excess of 20,000 in 2022.³ In England, 12% of the adult population (5.1 million) have prediabetes. If extrapolated to Scotland the estimate is around 500,000.⁴ The number of people living with type 2 diabetes in Scotland increased by a third between 2011 and 2021.⁵ Taking into account projected population changes over the next 20 years, Public Health Scotland estimates that the number of people living with diabetes in Scotland will increase by 36% by 2044.⁵ The average age at which people are diagnosed is also decreasing, and is associated with a poorer prognosis. A diagnosis of type 2 diabetes at age 40 reduces life expectancy by around 10 years, driven by the increased risk of cardiovascular disease (CVD).⁶

The annual economic cost to Scotland of type 2 diabetes is estimated at £2.37 billion taking into account loss of productivity as a result of impaired health, direct healthcare costs and investment to mitigate the impact of obesity.⁷ The cost to the NHS in Scotland of diabetes treatment alone is estimated at £1.6 billion (around 10% of total health expenditure).⁷ Without further efforts to prevent type 2 diabetes and improve care for people with diabetes, these figures are predicted to grow.⁷

Type 2 diabetes does not affect our population equally. In Scotland, people living in the most deprived communities having a 77% greater chance of developing diabetes than those in the most affluent areas. The short-term mortality risk from type 2 diabetes is higher among those living in more deprived areas, with the impact on disability-adjusted life years in these communities also 2.5 times greater.⁸ Uptake and completion of structured education and weight-management programmes is poorer in the most deprived areas (Scottish Index of Multiple Deprivation (SIMD) areas 1 and 2) despite around 50% of all referrals originating from people living in those areas.⁹

Many of the factors that drive type 2 diabetes risk cannot be controlled by the individual. These social determinants of health are the social, cultural, political, economic and environmental conditions into which people are born, grow up, live, work and age, and their access to power, decision making, money and resources that shape the conditions of their daily life. The social determinants of health influence a person’s opportunity to be healthy, their risk of illness, health behaviours and healthy life expectancy. Health inequities result from the uneven distribution of these social determinants.¹⁰ These have a significant impact on the ability to prevent and manage type 2 diabetes effectively.

Figure 1: The social determinants of health (adapted by Scottish Government)¹¹ from The University of Wisconsin Population Health Institute,¹² Booske et al, 2010¹³ and the King’s Fund¹⁴

At the individual level, non-modifiable risk markers such as increased age, ethnicity and genetic predisposition contribute to a person’s overall likelihood of developing type 2 diabetes. Even though some people may feel healthy, they can still be at risk of developing the condition.

At the time of type 2 diabetes diagnosis, people from minority ethnic populations, particularly those of South Asian ethnicity, in the United Kingdom (UK) are, on average, younger, have a lower body mass index (BMI), and higher haemoglobin A1c (HbA1c) levels than white or European populations (see Tables 1 and 2).^15-24

Table 1: Average age range at diagnosis of type 2 diabetes in the UK15-22,24

Table 2: Mean BMI cut-offs for overweight and classes of obesity in the UK

^a Indian, Pakistani, Bangladeshi, Nepali, Sri Lankan, and Tamil.

^b Indian, Pakistani and Bangladeshi.

In Scotland 87% of people with type 2 diabetes are living with overweight or obesity, with 67% of the overall Scottish adult population living with a BMI over 25 kg/m².²⁵

While healthcare professionals are unable to change the social determinants of health or non-modifiable risk factors, there is an opportunity to support some people to live healthier lives, in ways appropriate to their circumstances which might include weight loss.

 Current provision of weight management services for the prevention and treatment of type 2 diabetes differs across NHS boards. This includes variation in the type of programmes that are offered, duration and follow up, healthcare professionals involved in delivery, eligibility and access criteria for those services and where and how the services are delivered.

Digitally enabled care for people with diabetes has rapidly increased and this will feature permanently in future delivery models, particularly as the needs of a growing number of people are sought.

This evidence-based guideline has the potential to improve and standardise the approach to identifying people at the highest risk of developing type 2 diabetes and ensure that programmes targeting type 2 diabetes prevention are more likely to be effective. There is also the potential to ensure more equitable access to services for people at high risk of, and living with, type 2 diabetes.

A positive patient experience in healthcare communications leads to better health outcomes and enhanced clinical effectiveness. Communication of the recommendations in this guideline should be underpinned by best practice delivered through person-centred conversations. Healthcare professionals should adopt a collaborative, tailored and trauma- informed approach, recognising the person’s individual and social context and resources.

Positive interactions are likely to improve psychological wellbeing and be more effective in developing knowledge, skills and confidence to support behaviour change. These include communicating potentially difficult information about increased risk and avoiding stigma. Training resources to support person-centred conversations that respect the impact of lived experience of trauma are available:

·     Having Realistic Conversations | Turas | Learn (nhs.scot)

·     Module 1: Good conversations and empathy | Right Decisions (scot.nhs.uk)

·     Trauma – national trauma transformation programme | NHS Education (scot.nhs.uk)

While lifestyle changes, especially weight loss, are a core part of the recommendations made in this guideline, it is important to consider when additional caution may be required in providing advice to minimise the risk of unintended harms. It is essential to ask permission before starting any discussions linked to overweight, obesity and central adiposity.²⁶ The stigma associated with living with obesity can be distressing for many people and can impact outcomes. It is essential that all healthcare professionals have an awareness and understanding of this and undertake suitable training on how to practice in a non- stigmatising way. Weight stigma, bias and discrimination can cause considerable harm including compromised psychosocial wellbeing, depressed mood, increased metabolic risk factors and lower self-esteem.²⁷ Public Health Scotland host a weight stigma learning hub, that is free to access, for all health professionals (see section 6.2.3).

Additional caution is recommended in conversations with those who have, have had, or are suspected of having, an eating disorder of any kind. Weight-loss attempts may be contraindicated and may exacerbate or maintain the condition.²⁸ Prevalence of eating disorders in people living with overweight or obesity and in those at increased risk of, or with a diagnosis of, type 2 diabetes is unclear. Studies have shown that adults with binge eating disorder (BED) have a higher prevalence of type 2 diabetes.²⁹ People with lived experience have reported that their diabetes was diagnosed prior to their eating disorder being formally diagnosed, despite having lived with an eating disorder for decades.³⁰

People with both type 2 diabetes and an eating disorder are likely to need treatment for their eating disorder first, with the most appropriate service for this varying depending on local pathways in each health board. Weight-management services with specialist psychology resource can support treatment of binge eating difficulties, including BED, when this is picked up as part of the assessment process. However, there can often be a significant wait for an assessment. Consider local referral pathways, waiting times and the person’s preferences when deciding between a referral to weight-management services, eating disorder services or mental health services.

This guideline provides recommendations based on current evidence for best practice in the prevention, early detection and early non-pharmacological and pharmacological treatment to reduce the risk of type 2 diabetes. It covers adults who are:

·     at risk of developing type 2 diabetes

·     clinically diagnosed with prediabetes, impaired glucose tolerance, impaired fasting hyperglycaemia or previous gestational diabetes

·     recently diagnosed with type 2 diabetes.

It excludes children and the not-at-risk general population.

Management of type 1 diabetes (see SIGN 116 and SIGN 170) and the pharmacological treatment of people with type 2 diabetes (see SIGN 154) are not covered.

Further advice on the management of people with diabetes in pregnancy is available in SIGN 171.

This guideline will be of interest to healthcare professionals in primary care, weight management services, psychology, maternal health and diabetes specialist clinics. It will also be of interest to those working in a wider community setting supporting comprehensive weight-management services, such as at leisure centres, community centres, workplaces and faith centres.

People with lived experience may have different perspectives on healthcare processes and outcomes from those of healthcare professionals. The involvement of people with lived experience in guideline development is therefore important to ensure that guidelines reflect their needs and concerns and address issues that matter to them.

Common concerns raised by groups and organisations as part of this process included:

·     ensuring that conversations are person centred and sensitive

·     the need for timely information, support and advice

·     practical implications of being at risk of type 2 diabetes

·     the mental health of people who have been diagnosed with type 2 diabetes

·     the way people care for themselves before and after diagnosis is connected to quality of life.

A plain language version of this guideline is available.

An equality impact assessment for the development of this guideline is available in the supporting material section for this guideline on the SIGN website, https://www.sign.ac.uk/our-guidelines/type-2-diabetes-prevention/

This guideline is not intended to be construed or to serve as a standard of care. Standards of care are determined on the basis of all clinical data available for an individual case and are subject to change as scientific knowledge and technology advance and patterns of care evolve. Adherence to guideline recommendations will not ensure a successful outcome in every case, nor should they be construed as including all proper methods of care or excluding other acceptable methods of care aimed at the same results.

The ultimate judgement must be made by the appropriate healthcare professional(s) responsible for clinical decisions regarding a particular clinical procedure or treatment plan. This judgement should only be arrived at through a process of shared decision making with the patient, covering the diagnostic and treatment choices available. It is advised, however, that significant departures from the national guideline or any local guidelines derived from it should be documented in the patient’s medical records at the time the relevant decision is taken.

It is recognised that financial or academic interests may have an influence on the interpretation of evidence from clinical studies.

It is not possible to completely eliminate any possible bias from these sources, nor even to quantify the degree of bias with any certainty. SIGN requires that all those involved in the work of guideline development should declare all financial and academic interests, whether direct or indirect, annually for as long as they are actively working with the organisation. By being explicit about the influences to which contributors are subjected, SIGN acknowledges the risk of bias and makes it possible for guideline users or reviewers to assess for themselves how likely it is that the conclusions and guideline recommendations are based on a biased interpretation of the evidence.

Signed declarations of interests are retained by the SIGN Executive and are available on request.

Recommendations within this guideline are based on the best clinical evidence. Some recommendations may be for medicines prescribed outwith the marketing authorisation also known as product licence. This is known as ‘off-label’ use.

Medicines may be prescribed ‘off label’ in the following circumstances:

·     for an indication not specified within the marketing authorisation

·     for administration via a different route

·     for administration of a different dose

·     for a different patient population.

An unlicensed medicine is a medicine which does not have marketing authorisation for medicinal use in humans.

Generally, ‘off-label’ prescribing of medicines becomes necessary if the clinical need cannot be met by licensed medicines within the marketing authorisation. Such use should be supported by appropriate evidence and experience.³¹

“Prescribing medicines outside the conditions of their marketing authorisation alters (and probably increases) the prescribers’ professional responsibility and potential liability.”³¹

The General Medical Council (GMC) recommends that when prescribing a medicine ‘off label,’ doctors should:³²

·     be satisfied that there is no suitably licensed medicine that will meet the patient’s need

·     be satisfied that there is sufficient evidence or experience of using the medicine to show its safety and efficacy

·     take responsibility for prescribing the medicine and for overseeing the patient’s care, including monitoring the effects of the medicine, and any follow-up treatment, or ensure that arrangements are made for another suitable doctor to do so

·     make a clear, accurate and legible record of all medicines prescribed and, when not following common practice, the reasons for prescribing an unlicensed medicine.

Non-medical and medical prescribers should ensure that they are familiar with the legislative framework and the Royal Pharmaceutical Society’s Competency Framework for all Prescribers.³³

Prior to any prescribing, the licensing status of a medication should be checked in the Summary of Product Characteristics (SmPc) (www.medicines.org.uk). The prescriber must be competent, operate within the professional code of ethics of their statutory bodies and the prescribing practices of their employers.³⁴

Specialist teams within Healthcare Improvement Scotland issue a range of advice that focuses on the safe and effective use of medicines and technologies in NHSScotland.

The Scottish Medicines Consortium (SMC) provides advice to NHS boards and their Area Drug and Therapeutics Committees about the status of all newly licensed medicines, all new formulations of existing medicines and new indications for established products.

NHSScotland should take account of this advice and ensure that medicines accepted for use are made available to meet clinical need where appropriate.

The Scottish Health Technologies Group (SHTG) provides advice to NHSScotland on the use of new and existing health technologies (excluding medicines), likely to have significant implications for people’s care.