What is impaired awareness of hypoglycaemia?

Impaired awareness of hypoglycaemia (IAH) is the reduced ability to perceive the onset of hypoglycaemia.

How does IAH arise?

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IAH arises when repeated episodes of hypoglycaemia raise the glycaemic threshold for symptoms to occur. This means symptoms are only triggered at a lower blood glucose level than normal, causing symptoms not to occur when they should.

Avoidance of hypoglycaemia can reverse IAH2, though this strategy may run the risk of compromising glycaemic control.

Who does IAH affect?

IAH only happens in people regularly taking hypoglycaemic agents such as insulin, and a careful clinical history is often sufficient to identify IAH.2

IAH has varying occurrence by diabetes type:


of individuals with
Type 1 diabetes1


of individuals with
Type 2 diabetes1

What are the possible risks of IAH?

risk of IAH increased reliance on others for assistance
risk of IAH loss of driving privileges
risk of IAH loss of employment due to disability