What is diabetes?

What is diabetes?

Diabetes mellitus is a metabolic disorder that is characterised by the presence of high blood sugar due to defective insulin secretion, defective insulin action or both.

Why do we care about diabetes?

The presence of chronically high blood sugar is associated with long-term complications that affect the eyes, kidneys, nerves, and increase the risk for heart disease. Optimal blood sugar control is important to the management of diabetes.

What are the target values for blood sugar measurement?

  • Treatment in most individuals with type 1 or 2 diabetes should be targeted to achieve A1C ≤0% in order to reduce the risk of microvascular and macrovascular complications.
  • An A1C ≤5% may be targeted in some individuals with type 2 diabetes to further lower the risk of eye disease, kidney disease, and nerve damage.
  • A1C targets 7.1%-8.5% may be appropriate in patients with type 1 or 2 diabetes with any of the following:
    • Limited life expectancy
    • Cannot function independently
    • Extensive heart disease
    • Multiple co-morbidities
    • History of severe and recurrent hypoglycaemia (low blood sugar)
    • Hypoglycaemia unawareness
    • Longstanding diabetes for whom is it difficult to achieve A1C ≤0% despite effective medication use
  • In order to achieve A1C of≤0%, people with diabetes should aim for:
    • Fasting or pre-meal blood sugar of 4.0-7.0 mmol/L
    • 2 hour after meal blood sugar target of 5.0-10.0 mmol/L
  • If A1C≤0% target cannot be achieved, then aim for:
    • 2 hour after meal blood sugar target of 5.0-8.0 mmol/L

Summary Chart of the above information:

  A1C (%) Before meal blood sugar (mmol/L) 2 hr after meal blood sugar (mmol/L)
For most patients with Type 1 and Type 2 diabetes ≤ 7.0 4.0-7.0 5.0-10.0

(5.0-8.0 if A1C is not at target)

Frail elderly or those with limited life expectancy ≤ 8.5 5.0-12.0

(Depending on level of frailty)


* Blood sugar targets should be individualized based on age, duration of diabetes, risk of severe hypoglycaemia (low blood sugar), presence or absence of cardiovascular disease, and life expectancy. For more information, ask your pharmacist.

Term Definitions
Fasting Plasma Glucose Blood sugar readings when you have not eaten anything for at least 8 hours
2 hours Post Prandial Plasma Glucose Blood sugar readings 2 hours after a meal
HbA1C (haemoglobin A1C) Indicator of your blood sugar control over the previous 2-3 months


Leave a Comment