Management of type 2 diabetes
Symptoms arising from hyperglycaemia should be controlled, while minimising the risk of hypoglycaemia. It is also important to reduce the risk of developing long-term cardiovascular and neurological complications through the use of appropriate lifestyle changes.
Blood Monitoring
There is some debate about the value of blood glucose monitoring in type 2 diabetics. Whilst it is recognised that self-monitoring of blood glucose provides tighter control of glucose levels and reduces the risk of diabetic complications it can also increase the risk of hypoglycaemic events in some patients. NICE advises that self-monitoring is not beneficial for most patients with type 2 diabetes and should only be recommended for patients4:
- Treated with insulin
- Who have suffered hypoglycaemic episodes
- Treated with oral hypoglycaemic drugs that can cause hypoglycaemia
- Who are ill or experiencing changes in their lifestyle or medication to confirm changes in blood-glucose
- For testing during activities to ensure safe blood-glucose concentration
Currently NICE does not recommend specific fasting and postprandial blood glucose level targets, however the Diabetes UK Council of Healthcare Professional advises that the general targets issued by NICE in the 2008 guidance should be maintained as a guide for healthcare professionals, these targets were:
- 4-7mmol/litre before meals
and - less than 9mmol/litre after meals.5
Target blood glucose levels will be individual for each patient and should be agreed between the patient and healthcare professional.
You can provide some general guidance on the frequency of blood glucose monitoring:
Patients taking insulin:
- Test two to four times daily (depending on insulin dosing).
- Include one test before breakfast and prior to other meals.
- Test if patient thinks their blood sugar is high or low.
- Test before any journey and every two hours on long journeys.
Patients taking a sulfonylurea:
- Test at least three times weekly.
- Vary test times, this can help show when there is a risk of hypoglycaemia.
Patients taking other therapies:
- No routine testing required.
- The patient should test once a day if they feel unwell, change treatment, takes steroids or believes that their blood glucose is abnormal.
Glycosylated haemoglobin (HbA1-c)
Haemoglobin is the oxygen carrying protein in red blood cells and it becomes irreversibly bound to glucose (glycolated) to form glycosylated haemoglobin. The percentage of haemoglobin that is glycosylated is dependent upon the circulating glucose concentration. The glucose remains attached to the haemoglobin for the lifetime of the red blood cell, typically 120 days, consequently an HbA1c gives an indication of how well blood glucose has been controlled over the previous two to three months, and is seen as a definitive indicator of long term diabetes control.
HbA1c levels are routinely measured at 3-6 monthly intervals until the HbA1c is stable and the patient's treatment is not changing, after this the levels are checked 6 monthly.
In healthy non-diabetic patients it is present at concentrations of 42-53mmol/mol of the total circulating haemoglobin.
The ideal HbA1-c is open to debate and will vary between patients. Patients should be actively involved in decisions about their individual HbA1c target. Current NICE guidance (NG28) recommends the following target levels:
- Patients managed by lifestyle and diet or by lifestyle and diet combined with a single drug not associated with hypoglycaemia e.g. metformin 48mmol/mol
- Patients treated with an antidiabetic drug associated with hypoglycaemia e.g. sulphonylurea 53mmol/mol
Less stringent targets may be appropriate for patients who are old or frail, patients with limited life expectancy or advanced diabetic complications, where tight blood glucose control poses a significant risk of hypoglycaemia or if intensive management is inappropriate such as in patients with significant comorbidities.