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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)

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.