Preventing the complications of diabetes

Last time we looked at the prevention of type 2 diabetes, but this month we focus on the prevention of its complications, which pose an enormous burden – both in terms of the health impact on those who suffer them and the costs of treatment on the NHS

Diabetes takes up around 10% of the total NHS budget,¹ but the majority of expenditure is on treating the complications of type 2 diabetes (T2D).² The key complications of diabetes are vascular in nature, including microvascular and macrovascular disease.³ Other less well-recognised complications include depression and so-called ‘diabetes burn out’ and non-alcoholic fatty liver disease (NAFLD).⁴ It is also important to consider the possible side effects of medication used to treat diabetes too, including the risk of hypoglycaemic events – ‘hypos’.⁵

The prevention of vascular complications is the ultimate long-term aim of diabetes care. These complications include those of the larger vessels such as coronary heart disease, stroke and peripheral vascular disease and those affecting the smaller vessels serving the eyes (retinopathy), kidneys (nephropathy) and peripheral nerves (neuropathy).³ Factors that have been shown to increase the risk of complications include poor glycaemic control, hypertension and dyslipidaemia and are all part of the so-called metabolic syndrome.⁵ The risk of developing these macro- and microvascular complications can be minimised through a combination of lifestyle changes and drug treatment.

MONITORING FOR MACROVASCULAR DISEASE

Identifying people with increased levels of risk of macrovascular disease who need more aggressive interventions is an important part of diabetes care. Cardiovascular risk can be assessed through the use of tools such as Qrisk.⁶ Before carrying out a Qrisk assessment, the patient should have been informed what it is and why the calculation is being made – in other words, that the result may indicate the need for more intensive lifestyle and pharmacological interventions.

MONITORING FOR MICROVASCULAR DISEASE

The GPN is the patient’s advocate and has a central role in monitoring for early signs of microvascular complications – retinopathy, nephropathy and neuropathy. All of these complications are linked to poor control of the key three risk factors – blood glucose control, lipids and blood pressure.⁷

Retinopathy

Retinopathy can be identified and managed at an early stage through annual retinal screening checks, so GPNs should remind people of why these checks are so important. Diabetes is the key cause of blindness in the working age population,⁸ but early detection of retinopathy means diabetes management can be optimised to minimise further deterioration and interventions such as laser therapy can be initiated where appropriate to treat the affected blood vessels. There are three main types of diabetic retinopathy: background retinopathy, diabetic maculopathy and proliferative retinopathy and the condition will progress through these stages unless early background retinopathy is identified and addressed, essentially by improving the control of risk factors. A useful tool which explains the grading systems and the appropriate action for each stage can be found at http://www.diabeticretinopathy.org.uk/gradingretinopathy.htm

Visual symptoms do not normally occur in the early stages of diabetic eye disease, which is why retinal screening is so important.⁹

Nephropathy

Nephropathy occurs when there is damage to the small blood vessels in the kidneys, affecting filtration.¹⁰ The two key tests to assess for renal impairment are the estimated glomerular filtration rate (eGFR) which is a blood test, and the albumin creatinine ratio (ACR) which is a urine test. Urea and electrolyte levels can also be used to give a broader view of renal function. A normal eGFR is more than 90ml/minute but an acceptable level would be 60ml/minute as long as there is no other evidence of renal damage such as proteinuria.¹¹ Measuring eGFR is important for several reasons. Firstly, renal impairment is a marker for microvascular complications and may also indicate an increased risk of developing macrovascular complications in the future.¹² Furthermore, impaired renal function may affect the choice of drug treatments being used to manage the diabetes as several drugs are metabolised by the kidneys, including metformin, sulfonylureas (SUs) and insulin.¹³ Renal impairment may mean that these therapies continue to be active in the blood for longer than normal, increasing the risk of lactic acidosis (metformin) and hypoglycaemia (SUs and insulin).¹⁴ The DPP4 inhibitors (sitagliptin, for example) often need dose adjustments to be made in renal impairment, as smaller doses are as effective as larger doses in this group of people.¹⁵ Linagliptin is metabolised almost exclusively by the liver, however, so no dose adjustment is required.¹⁶ The ACR urine test is used to detect small amounts of small proteins in the urine that are leaking through the damaged filtering system of the kidneys. If action is not taken to treat it, and prevent further deterioration, the filtering ‘holes’ will increase in size, allowing more and bigger proteins to be excreted and microalbuminuria will develop into proteinuria. Annual ACR tests should be carried out to identify people with levels of 2.5mg/mmol or more, as these people are at increased risk of further microvascular and macrovascular complications.¹⁷ Tight blood pressure control (<130/80mmHg) using optimal doses of ACE inhibitors will reduce this risk.¹⁸

Neuropathy

Neuropathy affects small blood vessels serving the peripheral nerves, most commonly those in the lower limbs. Foot checks, which assess pulses and sensation, can help to identify low, medium and high risk limbs which may need further intervention and assessment. The posterior tibial and dorsalis pedis pulses should be palpated carefully; if there is any inability to identify the pulses a Doppler machine should be used to listen for them.¹⁹ A 10g monofilament can be used to assess for sensation.²⁰ Any concerns should be highlighted in the records and acted upon as necessary. Diabetes is a key cause of amputations, yet many of these could be avoided with appropriate foot checks and foot care advice. Other neuropathic complications include erectile dysfunction, neuropathic pain and autonomic neuropathy leading to gastroparesis all of which come with associated distress and morbidity.²¹

Diabetes UK’s State of the Nation report showed that many people were not being given all of the recommended key care components, including checks for microvascular complications, leaving them at risk of blindness, end stage renal disease and amputations in the future.²² Every opportunity should be taken to ensure these checks are carried out at least once a year and GPNs are well placed both to identify people who have been missed and to complete these checks over the year.

LIFESTYLE INTERVENTIONS

Lifestyle changes are absolutely central to preventing the complications of diabetes and all individuals should be encouraged to consider how they can improve their diet and increase their activity levels.²³ It could be argued that prevention of diabetes is the first step on the road to reducing the complications of diabetes and lifestyle changes have been shown to be more effective than medication in helping to prevent diabetes in high risk individuals. As previously discussed, weight loss of 5-10%, ideally on a rolling programme, a healthy low saturated fat diet which includes more fruit and vegetables – especially vegetables, and increased activity levels of around 150 minutes per week are all important as they are directly linked to the known risk factors that increase rates of cardiovascular disease.²⁴ Smoking cessation is also one of the most important interventions to reduce CVD risk,25 and people should be supported to stop smoking using a combination of behavioural change techniques and therapies such as dual nicotine replacement therapy or varenicline.²⁶ All people with diabetes should implement key lifestyle changes such as healthy eating, weight reduction and an increase in activity levels but a Qrisk score of 10% or more indicates that medication should be initiated unless contraindicated or declined.

PHARMACOLOGICAL INTERVENTIONS

The STENO-2 study confirmed the importance of a multifaceted approach to reducing CVD risk through improved glycaemic control, BP management and lipid lowering drugs.⁷

NICE has previously recommended target levels of 4mmol/l or less for total cholesterol and/or 2mmol/l or less for LDL cholesterol. In the updated guidelines on lipid management, NICE recommends initiating statin therapy (atorvastatin 20mg) in all patients with a 10% or greater 10-year risk of developing CVD, with the aim of reducing non-HDL cholesterol by 40% or more.²⁷ Higher doses of atorvastatin, other high intensity statins or additional therapies such as ezetimibe may be needed if this reduction in non-HDL cholesterol is not achieved. People with diabetes may also need treatment for hypertension and NICE guidelines state that angiotensin converting enzyme (ACE) inhibitors are the drug of choice as they are both cardioprotective and renoprotective.²⁸ The impact of these interventions in reducing the risk of CVD should not be underestimated as dyslipidaemia and hypertension are both at least as important, and in some cases more important, than glycaemic control in preventing CVD complications.⁵ Nonetheless, treating hyperglycaemia is an essential part of managing T2D and reducing the risk of macro- and microvascular complications. There are several classes of drugs that can reduce blood glucose levels. At the time of writing the updated and redrafted NICE guidelines on treating T2D are out for consultation, the previous draft having been heavily criticised.²⁹ This criticism reflected the fact that drug therapies for glycaemic control should not be selected purely on the basis that they reduce hyperglycaemia. Other issues that need to be considered are the likelihood of therapies causing undesirable treatment effects, which may impact on adherence and efficacy. These side effects include the propensity to cause hypos and weight gain, for example. While awaiting the publication of the new NICE guidance, the American Diabetes Association and European Association for the Study of Diabetes (ADA/EASD) guidelines offer guidance on taking a personalised approach to tailoring treatment to the individual.³⁰

OTHER COMPLICATIONS OF DIABETES

Diabetes ‘burnout’

Many people with a long-term condition will suffer from depression as a co-morbidity and people with diabetes are no exception.³¹ There is a particular type of depression seen in people with diabetes known as diabetes burnout, when the sheer effort of day to day living with diabetes can overwhelm the person and lead to them giving up on managing the condition.³² It can be deeply upsetting for families and loved ones to see someone stop taking medication, stop self-testing and give up on the health behaviours that can help to minimise risk, and although people suffering from diabetes burnout may experience an initial euphoria from ignoring their diabetes, the ultimate outcome will be poorer control and an increased risk of devastating complications. People with diabetes burnout may benefit from behavioural interventions such as motivational interviewing, cognitive behavioural therapy and mindfulness training but none of these will work without the engagement of the person concerned – which may be a challenge.³³

Non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is much more common in people with type 2 diabetes than in the general population and is associated with a higher prevalence of CVD.⁴ However, liver function tests may not always alter in NAFLD, making it hard to diagnose. The presence of abnormal LFTs in people with diabetes should trigger consideration of further investigations and possibly more aggressive management of CVD risk factors. Lifestyle interventions are the key to treating NAFLD.³⁴ However, any use of statin therapy will need to be monitored carefully in these individuals.

CARE PLANNING

One way in which people may be encouraged to engage with their diabetes and to get involved in their care is through care planning. The State of the Nation report showed that less than 1 in 20 people with diabetes was being offered care planning to support self-management.²² An agreed care plan between the individual and their health care team can be an important step to optimising the management of any long term condition.

By providing these plans, people should be able to discuss the targets and priorities for treatment with their health care providers to ensure that they are at the centre of every decision being made and that they have ‘bought in’ to the aims and objectives of their care. The NHS Choices website has information on how to develop a care plan,35 and Diabetes UK has made available some free resources to help with planning how to best manage blood glucose, BP and lipids (see resources, below).

CONCLUSION

GPNs are often the main point of contact for people with diabetes. Each review offers the opportunity to assess the way in which the risk of the complications of diabetes is being evaluated and treated. Explanation of the importance of glycaemic control through lifestyle and pharmacological interventions is essential along with the role of guardian drugs such as ace inhibitors and statins in preventing vascular complications. It may be possible to increase rates of adherence through explanation and education as well as through joint decision making about the types of medication to be used. CVD risk can be assessed using tools such as Qrisk along with monitoring for early signs of microvascular disease through blood tests, urine tests and screening for early changes before they become major problems. Care planning is an effective way of delivering personalised care, tailored to each individual and which they have been involved in developing.

REFERENCES

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35. NHS Choices. What is a care plan? 2014 http://www.nhs.uk/Planners/Yourhealth/Pages/Careplan.aspx