Type 2 Screening

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1. Rationale
2. Recommedations
3. Detection Programmes
4. Screening Strategies

Rationale

Screening for type 2 diabetes has important implications for individual health, day-to-day clinical practice, and public health policy. While the early detection and treatment of diabetes seems logical in terms of minimising complications, there is currently no evidence as to whether or not this is beneficial to individuals. Despite the lack of direct evidence, early detection though screening taking place and is recommended by a number of organisations throughout the world.

The decision about conducting a detection programme should be based on the following considerations:

• Epidemiological – prevalence of undiagnosed Type diabetes
• Health systems – capacity to carry out the screening, provide care for those who screen positive, and implement prevention programmes in those at high risk of future development of diabetes
• Population – acceptability and likely uptake of the screening programme
• Economic – cost of early detection to the health system and to the individual, and relative cost-effectiveness of early detection compared with improving care for people with known diabetes.

Recommendations

• Universal screening for undiagnosed diabetes in the Bath area is not recommended at this juncture
• Detection programmes should target only high risk people identified by risk assessment factors

5. 1. Everyone aged over 65 years
   2. Pregnant women (see pregnancy re screening criteria)
   3. Women with a history of gestational diabetes or who have given birth to a large baby (birthweight>4kg)
   4. Patients with symptoms of:
      • Thirst, polyuria and or weight loss
      • Urinary symptoms. E.g. nocturia, urinary incontinence
      • Recurrent infections, especially skin
      • Pain, numbness and parasthesiae (pins and needles)
      • Visual changes
      • Mood changes
      • Tiredness, muscle weakness
      • People who are obese, especially central obesity (the apple shaped body) (BMI > 25kg/m2) (30 is a starting point) In particular target those patients with the metabolic syndrome: Waist circumference Men > 102 cm (> 40 in) Women > 88 cm (> 35 in),Triglycerides >1.7 mmol or Low HDL cholesterol Men < 1.04 mmol/L Women < 1.30 mmol/L, Blood pressure ³ 130/³ 85 mmHg
   5. People of Asian, African and Afro-Caribbean origin (age over 25)
   6. Anyone with a family history of diabetes or cardiovascular disease (age over 40)
   7. Women with PCO (Polycystic Ovarian Syndrome) .

Screening should be carried out in patients with an underlying diagnosis of:

• Hypertension
• Angina
• Heart attack
• Claudication
• Stroke

Note: Fasting Cholesterol is required for these patients, add in fasting glucose as well

• People of Asian origin are more likely than others to develop type 2 diabetes, and at an earlier age
• Flag the notes of those with a history of gestational diabetes
• Screen those at risk of developing diabetes every 3 years

Detection programmes

• Detection programmes should use measurement of plasma glucose, preferably fasting.
• For diagnosis, an oral glucose tolerance test (OGTT) should be performed in people with a fasting plasma glucose > 6 mmol/l and <7.0 mmol/l
• Where random plasma glucose level > 5.6 mmol/l and <11.1 mmol/l is detected on opportunistic screening, it should be repeated fasting, or an OGTT performed.
• The WHO 1999 criteria should be used to diagnose diabetes; these include the importance of not diagnosing diabetes on the basis of a single laboratory measurement in the absence of symptoms
• People with screen-detected diabetes should be offered treatment and care

Screening strategies

There are several options for strategies to screen for undiagnosed diabetes. The ultimate choice is based on available resources and trade-off between sensitivity (the proportion of people with diabetes who test positive on the screening test), specifically (the proportion of people who do not have diabetes who test negative on the screening test), and the proportion of the population with a positive screening test which needs to proceed to diagnostic testing.

Most screening strategies include risk assessment and measurement of plasma glucose, performed either sequentially or simultaneously. Screening tests are followed by diagnostic tests (fasting plasma glucose (FPG) and/or an oral glucose tolerance test (OGTT) in order to make the diagnosis (World Health Organisation. Screening for Type 2 Diabetes. Report of a World Health Organisation and International Diabetes Federation meeting. WHO/NMH/MNC/03.1 Geneva: WHO Department of Noncummunicable Disease Management, 2003. http://www.who.int/). Combined screening strategies have sensitivity and specificity in the order of 75%, and 25% of the population require diagnostic testing. People who screen negative will need re-testing after 3-5 years. These people should also be offered lifestyle advice to minimise their risk of developing diabetes.

Although the usefulness of urine glucose as a screening test for undiagnosed diabetes is limited because of low sensitivity (21-64%) (Englegau MM, Narayan KMV, Herman WH. Screening for Type 2 diabetes. Diabetes Care 2000; 23: 1563-80), specificity is high (>98%), so it may have a place in low-resource settings where other procedures are not available.