What are diabetes-related diseases and how can we prevent them?

Diabetes prevalence increases with age as do complications related to the condition. Hyperglycaemia, or raised blood sugar, is a common effect of uncontrolled diabetes and over time leads to serious damage to many of the body’s systems, especially the nerves and blood vessels.¹

Managing these complications may present special challenges in older people as even the most effective treatments only reduce rather than abolish risks.

There are currently 3.4 million people with type 2 diabetes in England with around 200,000 new diagnoses every year. While type 1 diabetes cannot be prevented and is not linked to lifestyle, type 2 diabetes is largely preventable through lifestyle changes.²

Diabetes can also be treated and its consequences avoided or delayed with diet, physical activity, medication and regular screening and treatment for complications.

Diabetes-related complications include cardiovascular, cerebrovascular and peripheral vascular problems and are a major causes of morbidity for older people. These complications can take a while to appear but evidence suggests that increased cardiovascular risk is already apparent during the ‘pre-diabetes’ stage and a proportion of ‘newly diagnosed’ people with diabetes already have detectable retinopathy.

Prevention in midlife

Prevention in midlife is better than management of the condition later. It is important to raise earlier awareness of modifiable risk factors including non-diagnosis, lifestyle changes (smoking, diet, exercise), hypertension, hyperlipidaemia and hyperglycaemia.

This is why the NHS Diabetes Prevention Programme (NHS DPP) was set up. It is a joint commitment from NHS England, Public Health England and Diabetes UK, to deliver at scale evidence-based behavioural interventions for individuals identified as being at high risk of developing type 2 diabetes.

It is available nationwide across England for adults with haemoglobin A1c (HbA1c) between 42-47mmol/mol or fasting plasma glucose (FPG) between 5.5 – 6.9 mmol/l.

Those referred get tailored, personalised help to reduce their risk of type 2 diabetes including education on healthy eating and lifestyle, help with weight loss (for overweight participants), and bespoke physical exercise programmes. Over a minimum of nine months, patients will be offered at least 13 education and exercise sessions of one to two hours and at least 16 hours face to face or one-to-one in total.

The details of the programme can vary within this specification. In our area we supply a list of patients considered at high risk and they are called in for a blood test by the programme organisers. There is no upper age limit but patients are usually referred following a NHS Health Check programme that covers adults aged 40-74 years. This is why it is useful to consider annual glucose testing for older patient on hospital or care home admission.

Diabetes prevention in primary care

The Diabetes Remission Clinical Trial (DiRECT) was designed to determine whether a structured, intensive, weight management programme, delivered in a routine primary care setting, is a viable treatment for achieving durable normoglycaemia. Other aims were to understand the mechanistic basis of remission and to identify psychological predictors of response.³

A commercial micronutrient-replete 825-853kcal/d liquid formula diet (soups and shakes) was provided (Cambridge Weight Plan) to replace usual foods, with ample fluids (2.2 L), for 12 weeks. A soluble fibre supplement (Fybogel 2.5g—3.5g/day) was also prescribed to reduce constipation.

Oral hypoglycaemic agents, antihypertensive and diuretic drugs were withdrawn on commencement and reintroduced (as per study protocols) if type 2 diabetes or hypertension returned. Aspirin was continued if prescribed because of a previous myocardial infarction (prior to the previous six months), but discontinued if prescribed solely because of type 2 diabetes. Beta-blockers prescribed for the management of angina were continued.

Participants then returned for review one week after commencement of total diet replacement and at two weekly intervals thereafter until the commencement of the food reintroduction stage.

Two-year data was presented at the Diabetes UK meeting in March 2019. At 24 months, 17 (11%) intervention participants and three (2%) control participants had weight loss of at least 15kg and 53 (36%) intervention participants and five (3%) control participants had remission of diabetes. The adjusted mean difference between the control and intervention groups in change in bodyweight was ˆ’5·4kg and in HbA1C was ˆ’4·8mmol/mol despite only 51 (40%) of 129 patients in the intervention group using anti-diabetes medication compared with 120 (84%) of 143 in the control group.

In a post-hoc analysis of the whole study population, of those participants who maintained at least 10kg weight loss (45 of 272 with data), 29 (64%) achieved remission; 36 (24%) of 149 participants in the intervention group maintained at least 10kg weight loss.

Serious adverse events were similar to those reported at 12 months, but were fewer in the intervention group than in the control group in the second year of the study (nine vs 22).

The trial shows that highly motivated and supported patients can achieve remission of type diabetes in many instances over a 1-2 year period. However, involvement and completion rates are modest, required input is beyond that currently available in primary care, and dropout from the programme results in regain of weight and probably later ‘recurrence’ of diabetes.

It has been promoted as showing that a primary care intervention to support weight loss can result in the remission of type 2 diabetes in patients diagnosed within six years, which is exciting but the trial only included people up to age 65 years.

Aims of treatment

For those patients that do have type two diabetes, the main risks are cardiovascular disease, cerebrovascular disease, vascular dementia, peripheral vascular disease and renal impairment leading to dialysis. Diabetes is also a major cause of blindness (retinopathy) and can lead to neuropathy and chronic pain.

There are many considerations when deciding on management of a patient’s diabetes from issues around motivation and choices of the individual as well as social and cultural context to comorbidities and polypharmacy.

Aims of treatment are to improve health and well being while being realistic about the value of tight glycaemic control in the prevention of complications.

Metformin generally remains the first-line treatment with or after lifestyle optimisation. The primacy of metformin derives from a small sub-analysis of Primary Care Diabetes Society data covering something over 340 patients. However, since metformin is inexpensive, relatively effective and has a sound safety record, there is little pressure for change although some newer agents have more convincing evidence of net benefits.

There is no perfect agent. NICE is currently revising its 2015 guideline and it will be interesting to see whether the move towards newer and more expensive agents with some demonstrated benefits is felt to be cost effective.

As GPs and diabetes nurse specialists, we are ideally placed to consider with our patients appropriate treatment targets and priorities. It is also our job to simplify and ‘de-risk’ treatments for frailer people and in our highest risk patients consider specific classes of treatments.

Dr Martin Hadley-Brown, School Lane Surgery and Clinical Tutor and Director of Preclinical Studies, Hughes Hall, University of Cambridge 

1. https://www.who.int/news-room/fact-sheets/detail/diabetes
2. https://www.england.nhs.uk/diabetes/diabetes-prevention/
3. Leslie, W.S., Ford, I., Sattar, N. et al. The Diabetes Remission Clinical Trial (DiRECT): protocol for a cluster randomised trial. BMC Fam Pract 17, 20 (2016) doi:10.1186/s12875-016-0406-2