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Early identification of people at high risk of type 2 diabetes or with type 2 diabetes

The need for early identification

  • Many people with type 2 diabetes remain undiagnosed. People with type 2 diabetes may have the condition for 5–10 years before diagnosis—by the time they are diagnosed, 50% of people have evidence of complications such as retinopathy, neuropathy or arterial disease
  • Impaired glucose tolerance (IGT) and impaired fasting glycaemia (IFG)—also collectively known as prediabetes, are associated with an increased risk of developing type 2 diabetes and cardiovascular disease. Early management can reduce progression to diabetes by up to 60%

Whom to test

  • Diabetes UK recommends a proactive and systematic approach to ensure the early identification of people with diabetes as well as people who are at high risk of developing type 2 diabetes, e.g. those with prediabetes. This includes a stepped approach using a risk assessment tool followed by an appropriate blood glucose test
  • Diabetes UK welcomes diabetes risk assessment as part of NHS Health Checks in order to identify people at risk and with type 2 diabetes. The Diabetes Risk Score can be used as a risk assessment tool in order to identify these people. The Diabetes Risk Score can be found at www.diabetes.org.uk/Riskscore/

Risk factors for type 2 diabetes include:

  • People who:
    • are overweight (BMI >25 kg/m2) waist measurement of ≥94 cm (≥37 inches) for White and Black men; ≥80 cm (≥31.5 inches) for women; and ≥90 cm (≥35 inches) for South Asian men
    • have a first-degree family history of diabetes
    • are over 40 years of age, or over 25 years of age for those of South Asian origin
    • are of South Asian origin (they are six times more likely to develop type 2 diabetes); or those of Black–African or Caribbean (they are three times more likely to develop type 2 diabetes)
    • have ischaemic heart disease, cerebrovascular disease, peripheral vascular disease, and treated for hypertension
    • are known to have IGT or IFG (prediabetes)
    • have severe mental health problems
  • Women:
    • who have had gestational diabetes (screen within 6 weeks of delivery and then at 1 year post-partum and then 3-yearly); or have had a large baby (i.e.more than 4.5 kg)
    • with polycystic ovary syndrome who are also obese (BMI>30)
  • The more risk factors that apply, the greater the risk of developing type 2 diabetes

How often to test

  • Diabetes UK currently recommends reassessment of risk every 3 years, using a risk assessment tool, for those who are at high risk of developing type 2 diabetes
  • Diabetes UK recommends people identified with prediabetes should have an annual assessment and blood test (or sooner if they develop symptoms of diabetes)

How to test

  • Once people are identified at high risk of type 2 diabetes, the most appropriate blood testing methods are:
    • fasting plasma blood glucose
    • an oral glucose tolerance test (OGTT)
    • HbA1c
  • For all these tests, the World Health Organisation (WHO) diagnostic criteria should be used

Where to test

  • Diabetes UK recommends opportunistic risk assessment for diabetes using a risk assessment tool, whether it is as part of the NHS Health Check, record and register-based, self-assessment or opportunistic screening, which includes assessment at the workplace, community events and in pharmacies
  • Staff need to be adequately trained in both carrying out the measuring technique, and giving advice and support to those with abnormal results

Response to risk assessment results:

  • It is important to consider the impact that a high risk assessment score result may have on an individual—consideration should be given to the provision of emotional and educational support at this stage
  • It is important that a risk assessment result is not seen as a diagnostic test—the person must be referred for appropriate confirmatory blood testing
  • Brief advice should be given to all people that have been risk assessed:
    • the person should be given written details of the risk assessment result, highlighting their risk of developing type 2 diabetes, how to modify it and the benefits of making lifestyle changes. People at a high risk of type 2 diabetes should make a routine appointment with the GP as soon as possible following the risk assessment (an earlier appointment may be suggested if the person is symptomatic)
    • the GP should confirm the diagnosis by a formal glucose assay performed by a reputable laboratory
    • no therapy should be instigated until a final diagnosis has been established

full guidelines available from…
Diabetes UK, 10 Parkway, London NW1 7AA (Tel –020 7424 1000)
http://www.diabetes.org.uk

Diabetes UK. Early identification of people at high risk of type 2 diabetes or with type 2 diabetes. 2009, updated November 2011
First included: October 2001.