Dr Kevin Fernando provides top tips on diagnosing and managing type 2 diabetes and identifying people at high risk
Read this article to learn more about:
- identifying people at risk of developing type 2 diabetes and gestational diabetes
- tailoring the HbA1c target to the individual
- structured education programmes and educational resources that can help patients to self-manage their diabetes.
The State of the nation 2016 (England)—time to take control of diabetes report from Diabetes UK warns that 5 million people in England are at high risk of developing type 2 diabetes mellitus (T2DM).1 High-quality evidence from several international diabetes prevention studies shows that early lifestyle intervention can reduce both long-term progression to T2DM,2 and long-term incidence of cardiovascular and all-cause mortality.3 Based on the evidence from five large-scale and tightly controlled randomised trials,3 the NHS Diabetes Prevention Programme4–6 was launched during 2016 to provide individualised lifestyle support for those at high risk of T2DM.
1 Identify people who are at high risk of T2DM on your practice register
NICE Public Health Guideline (PHG) 38 Type 2 diabetes: prevention in people at high risk recommends the use of a risk-assessment tool such as the QDiabetes-2016 risk calculator to identify patients at high risk of T2DM.7,8 The tool calculates an individual’s 10-year risk of developing diabetes; in general, 10% or above is considered high risk.7
NICE PHG38 provides a useful flowchart (see Figure 1, below) outlining recommended interventions for patients at various levels of risk of T2DM:8
- if low/medium risk, offer brief advice on the following, at least every 5 years—
- the risks of developing diabetes
- the benefits of a healthy lifestyle
- modifying risk factors
- if high risk, offer an HbA1c test—
- if HbA1c is <42 mmol/mol the patient is at moderate risk; offer a brief intervention and reassess risk at least every 3 years
- if HbA1c is 42–47 mmol/mol the patient is at high risk; offer an intensive lifestyle‑change programme such as the NHS Diabetes Prevention Programme5,6 and reassess once a year
- if HbA1c is ≥48 mmol/mol the patient has possible T2DM; further investigation is required (see below).
NB the flowchart (Figure 1, below) was created before the publication of the UK expert position statement on the use of HbA1c as a diagnostic tool.9 Current expert opinion supports the use of HbA1c to assess risk of diabetes rather than fasting plasma glucose testing, to keep matters simple in primary care.10
2 Use HbA1c to diagnose T2DM in non-urgent situations
The World Health Organization (WHO) published guidance in 2011 for the use of HbA1c as a diagnostic tool, recommending a threshold of 6.5% (48 mmol/mol).11 The WHO also states that a value of <6.5% (48 mmol/mol) does not exclude diabetes using glucose tests.11 This guidance was ratified in an expert position statement published by the UK Department of Health Advisory Committee on Diabetes in 2012.9
In asymptomatic individuals, or those with symptoms of T2DM for more than 2 months, check HbA1c levels:9
- if HbA1c ≥48 mmol/mol, this suggests probable T2DM. Repeat the test within 2 weeks to exclude a spurious result. If repeat test is also ≥48 mmol/mol, then a diagnosis of T2DM is confirmed
- if HbA1c <48 mmol/mol follow the flowchart in Figure 1 (see below).
- Importantly, during the development of the expert position statement on the use of HbA1c some group members raised objections to the use of the fasting glucose test as an alternative or add-on to the HbA1c test. Fasting is not universally complied with, in addition to being inconvenient for the patient, and as such conflicting test results can delay diagnosis.9 Therefore, to prevent conflicting and confusing results in primary care, practitioners should use HbA1c alone,9,10 except for the situations described in Box 1 (see below) where HbA1c should not be used for diagnosis.
Box 1: When not to use HbA1c for diagnosis9
HbA1c should not be used for the diagnosis of diabetes:
- in all children and young people
- in pregnancy, current or recent (<2 months)
- if T1DM is suspected, at any age
- if the duration of diabetes symptoms is short (<2 months)
- in people—
- at high risk of diabetes who are acutely unwell
- taking drugs that may precipitate a rise in glucose (e.g. corticosteroids, antipsychotic drugs)
- with acute pancreatic damage, or those who have had pancreatic surgery
- with renal failure
- with HIV infection.
HbA1c=glycated haemoglobin; T1DM=type 1 diabetes mellitus
Figure 1: Identifying and managing risk of T2DM8
3 Individualise HbA1c targets
NICE Guideline (NG) 28 on Type 2 diabetes in adults: management advocates adopting an individualised approach to diabetes care, tailored to the patient’s needs and circumstances.12 This is particularly important for people with significant comorbidities, people who are older or frail, those who have a reduced life expectancy, or those whose job involves driving or operating machinery, where a more relaxed HbA1c target may be considered on a case-by-case basis.12 As Sir William Osler said: ‘the good physician treats the disease; the great physician treats the patient who has the disease.’
Holistically, NICE NG28 recommends that clinicians ‘involve adults with type 2 diabetes in decisions about their individual HbA1c targets.’12 When setting an individualised HbA1c target:12
- for adults with diet-controlled T2DM, or those on a single drug not associated with hypoglycaemia, aim for a target HbA1c of 48 mmol/mol
- if HbA1c rises to above 48 mmol/mol on lifestyle interventions alone, offer standard-release metformin
- for adults taking a drug that causes hypoglycaemia (for example sulphonylureas), aim for a target HbA1c of 53 mmol/mol
- if HbA1c increases to 58 mmol/mol in patients treated with a single drug, first intensification of treatment to dual therapy is recommended (in addition to further advice about diet and adherence to treatment) and patients should be encouraged to aim for a new target of 53 mmol/mol
- if HbA1c exceeds 58 mmol/mol in patients on dual therapy, second intensification of treatment to triple therapy is recommended, aiming for a treatment target of 53 mmol/mol
- it is important to consider other underlying conditions that may be responsible for a patient having an HbA1c level below their target, such as worsening renal function or sudden unexplained weight loss which may require further investigation.
4 Review individualised targets and therapy regularly
The person’s needs and circumstances should be reassessed at each review, and treatment targets should be considered as part of the review.12
Functionally independent newly diagnosed patients with T2DM are likely to benefit from early, tight glycaemic targets, which have been shown to provide significant protection from microvascular disease associated with T2DM.13
Functionally dependent patients with long-standing T2DM and comorbidities have more to gain from blood pressure and lipid control rather than tight glycaemic control; in some cases, tight glycaemic control in these individuals may do harm.14
5 Offer appropriate self-monitoring of blood glucose
NICE NG28 Type 2 diabetes in adults: management recommends that healthcare practitioners refer to the DVLA’s At a glance guide to the current medical standards of fitness to drive15 when offering self-monitoring of blood glucose (SMBG) to adults with T2DM.12
Self-monitoring of blood glucose should only be routinely offered if:12
- the person is on insulin or
- there is evidence of hypoglycaemic episodes or
- the person is on an oral drug that increases the risk of hypoglycaemia while driving or operating heavy machinery (for example sulphonylureas) or
- the person is pregnant, or planning to become pregnant.
Healthcare practitioners can also consider short-term SMBG for patients starting treatment with steroids or to confirm suspected hypoglycaemia. Importantly, all patients undertaking SMBG require an annual assessment that should include:12
- self-monitoring skills and the equipment used
- quality and frequency of testing
- checking that the individual knows how to interpret blood glucose values, and crucially, knows what action to take
- the impact on the individual’s quality of life, and continued benefit.
6 Identify people at risk of gestational diabetes mellitus
Seeing women of child-bearing age either with established T2DM or at high risk of developing T2DM is becoming increasingly common. It is important to diagnose gestational diabetes mellitus (GDM) promptly as any degree of glycaemia in pregnancy can lead to adverse maternal and foetal outcomes.16 Risk factors for GDM are listed in Box 2 (see below).
Women diagnosed with GDM are at increased risk of developing T2DM in the future;18 however, many women with GDM are unfortunately lost to follow up after pregnancy,19 often understandably due to busy family lives.
NICE NG3 recommends that women with GDM are offered follow up including:17
- lifestyle advice and an FPG check at 6–13 weeks after birth; do not routinely offer an oral glucose tolerance test
- pragmatically, this could comprise part of the routine 6-week post-partum check
- if FPG is between 6.0 and 6.9 mmol/l, advise them that they are at high risk of developing T2DM and offer appropriate advice and guidance for prevention
- if FPG is ≥7 mmol/l, advise them that they are likely to have T2DM and offer a diagnostic test to confirm
- importantly, if the FPG test is negative they should be offered an annual HbA1c test.8
Box 2: Risk factors for gestational diabetes mellitus17
- Risk factors for GDM include:
- body mass index over 30 kg/m2
- previous macrosomic baby weighing 4.5 kg or above
- a family history of diabetes (first-degree relative with diabetes)
- a minority ethnic background with a high prevalence of diabetes (for example South or East Asian, Middle Eastern, African- Caribbean, Hispanic)
- previous GDM
- glycosuria of 2+ or above on one occasion (or 1+ or above on two or more occasions) during pregnancy
- Offer women with any one of these risk factors testing for gestational diabetes.
GDM=gestational diabetes mellitus
National Institute for Health and Care Excellence. Diabetes in pregnancy: management from preconception to the postnatal period. NICE Guideline 3. NICE, 2015. Available from: www.nice.org.uk/ng3
NICE has not checked the use of its content in this article to confirm that it accurately reflects the NICE publication from which it is taken
7 Structured education programmes
Lifestyle modification is the cornerstone of diabetes management, and as such, NICE NG28 recommends that practitioners offer all adults with T2DM, and their family members or carers, a structured education programme at and around the time of diagnosis, with annual reinforcement and review.12
Structured education programmes include DESMOND (www.desmond-project.org.uk) and X-PERT (www.xperthealth.org.uk). Ensure that the outcomes of structured education are audited on a regular basis.12
Access to structured education programmes is inconsistent throughout the UK and there can be a considerable delay between the time of diagnosis and the time of education. During this period, all adults with T2DM can be signposted towards resources to educate and reinforce the all-important lifestyle interventions required to self-manage diabetes, see the examples below:
- Diabetes UK webpage for newly diagnosed people (www.diabetes.org.uk/ Newly-diagnosed-with-diabetes)
- NHS Choices: the new Eatwell Guide 2016 (www.nhs.uk/ Livewell/Goodfood/Pages/the-eatwell-guide.aspx)
- British Dietetic Association food fact sheets (www.bda.uk.com/ foodfacts)
- Diabetes UK: Carbs count e-book (www.diabetes.org.uk/Guide-to-diabetes/Enjoy-food/ Carbohydrates-and-diabetes/ nuts-and-bolts-of-carb-counting/)
- British Heart Foundation: Perfect portion sizes (www. bhf.org.uk/heart-matters-magazine/nutrition/weight/ perfect-portions).
8 The management of cardiovascular risk factors in diabetes
Cardiovascular disease (CVD) remains the leading cause of death in people with T2DM. Overall, CVD risk is around double in people with T2DM compared with people without diabetes, independent of conventional risk factors.20
Departing from previous NICE guidance, NG28 recommends that practitioners should NOT offer aspirin or clopidogrel to people with T2DM without CVD.12 For advice on primary and secondary prevention of CVD in people with T2DM, NICE NG28 signposts practitioners towards NICE Clinical Guideline 181 on CVD risk assessment and reduction, and NICE CG172 on myocardial infarction.21,22
Lipid modification therapy
For people with T2DM:21
- primary prevention of CVD—
- estimate CVD risk scoring using the QRISK2 calculator (qrisk.org/2016); this will help to individualise lipid-lowering therapy rather than the traditional ‘fire and forget’ approach
- offer atorvastatin 20 mg to people with T2DM with a 10-year CVD risk ≥10%
- secondary prevention of CVD—
- offer atorvastatin 80 mg to people with either T1DM or T2DM who have CVD.21NB atorvastatin currently (May 2017) does not have UK marketing authorisation for this indication. The prescriber should follow relevant professional guidance, taking full responsibility for the decision. Informed consent should be obtained and documented. See the General Medical Council’s Good practice in prescribing and managing medicines and devices3 for further information.
As always, however, practitioners must take an individualised approach to the management of cardiovascular risk in diabetes, as many of the recommendations from NICE guidance are based on population studies that do not necessarily reflect the individual sitting in the consultation room.
Blood pressure management
People with T2DM should have their blood pressure managed as follows:12
- in adults without previously diagnosed hypertension or renal disease, check blood pressure (BP) at least annually
- recheck BP measurements within:
- 1 month if BP >150/90 mmHg
- 2 months if BP >140/80 mmHg
- 2 months if BP >130/80 mmHg and there is evidence of renal, eye, or cerebrovascular disease
- monitor BP every 4–6 months once the individual is stable
- reinforce preventative lifestyle advice at every given opportunity
- first-line antihypertensive drug treatment is a once-daily angiotensin-converting enzyme (ACE) inhibitor (or angiotensin receptor blocker if ACE inhibitor is not tolerated)
- individuals of African-Caribbean descent can be relatively resistant to ACE inhibitor monotherapy, so initial therapy should consist of an ACE inhibitor plus either a diuretic or calcium channel blocker.
- Diabetes UK. State of the Nation 2016—time to take control of diabetes. Available at: www.diabetes.org.uk/About_us/What-we-say/Statistics/State-of-the-Nation-2016-Time-to-take-control-of-diabetes/ (accessed 16 May 2017).
- Lindström J, Peltonen M, Eriksson J et al. Improved lifestyle and decreased diabetes risk over 13 years: long-term follow-up of the randomised Finnish Diabetes Prevention Study (DPS). Diabetologia 2013; 56 (2): 284–293.
- Li G, Zhang P, Wang J et al. Cardiovascular mortality, all-cause mortality, and diabetes incidence after lifestyle intervention for people with impaired glucose tolerance in the Da Qing Diabetes Prevention Study: a 23-year follow-up study. Lancet Diabetes Endocrinol 2014; 2 (6): 474–480.
- NHS DPP Programme Support Team. Primary care toolkit to support the local implementation of the NHS DPP. NHS, 2016. Available at: www.england.nhs.uk/wp-content/uploads/2016/07/dpp-pc-toolkit.pdf (accessed 16 May 2017).
- NHS England. NHS Diabetes Prevention Programme (NHS DPP). Available at: www.england.nhs.uk/ourwork/qual-clin-lead/diabetes-prevention/ (accessed 16 May 2017).
- Public Health England, Diabetes UK, NHS England. NHS Diabetes prevention programme—NHSDPP overview and FAQ. NHS, 2016. Available at: www.england.nhs.uk/wp-content/uploads/2016/08/dpp-faq.pdf (accessed 16 May 2017).
- ClinRisk Ltd. Welcome to the QDiabetes® -2016 risk calculator. Available at: www.qdiabetes.org/ (accessed 16 May 2017).
- NICE. Prevention of type 2 diabetes: prevention in people at high risk. NICE Public Health Guidance 38. NICE, 2012. Available at: www.nice.org.uk/ph38 (accessed 16 May 2017).
- John W, UK Department of Health Advisory Committee on Diabetes. Use of HbA1c in the diagnosis of diabetes mellitus in the UK. The implementation of World Health Organization guidance 2011. Diabet Med 2012; 29 (11): 1350–1357.
- Kilpatrick E, Atkin S. Using haemoglobin A1c to diagnose type 2 diabetes or to identify people at high risk of diabetes. BMJ 2014; doi: 10.1136/bmj.g2867
- World Health Organization (WHO). Use of glycated haemoglobin (HbA1c) in the diagnosis of diabetes mellitus—abbreviated report of a WHO consultation. WHO, 2011. Available at: www.who.int/cardiovascular_ diseases/report-hba1c_2011_edited.pdf (accessed 16 May 2017).
- NICE. Type 2 diabetes in adults: management. NICE Guideline 28. NICE 2015. Available at: www.nice.org.uk/ng28 (accessed 16 May 2017).
- UK Prospective Diabetes Study Group (UKPDS). Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet 1998; 352 (9131): 837–853.
- The Action to Control Cardiovascular Risk in Diabetes Study Group. Effects of intensive glucose lowering in type 2 diabetes. N Engl J Med 2008; 358 (24): 2545–2559.
- Driver and Vehicle Licensing Agency. Assessing fitness to drive—a guide for medical professionals. DVLA, 2017. Available at: www.gov.uk/government/uploads/system/uploads/attachment_data/file/596959/assessing-fitness-to-drive-a-guide-for-medical-professionals.pdf (accessed 16 May 2017).
- HAPO Study Cooperative Research Group. Hyperglycaemia and adverse pregnancy outcomes. N Engl J Med 2008; 358 (19): 1991–2002.
- NICE. Diabetes in pregnancy: management from preconception to the postnatal period. NICE Guideline 3. NICE, 2015. Available at: www.nice.org.uk/ng3 (accessed 16 May 2017).
- Bellamy L, Casas J, Hingorani A, Williams D. Type 2 diabetes mellitus after gestational diabetes: a systematic review and meta-analysis. Lancet 2009; 373 (9677): 1773–1779.
- McGovern A, Butler L, Jones S et al. Diabetes screening after gestational diabetes in England: a quantitative retrospective cohort study. Br J Gen Pract 2014; 64 (618): e17–23.
- The Emerging Risk Factors Collaboration. Diabetes mellitus, fasting blood glucose concentration, and risk of vascular disease: a collaborative meta-analysis of 102 prospective studies. Lancet 2010; 375 (9733): 2215–2222.
- NICE. Cardiovascular disease: risk assessment and reduction, including lipid modification. NICE Clinical guideline CG181. NICE, 2014. Available at: www.nice.org.uk/guidance/cg181
- NICE. Myocardial infarction: cardiac rehabilitation and prevention of further cardiovascular disease. Clinical Guideline 172. NICE, 2013. Available at: www.nice.org.uk/guidance/cg172