Impaired awareness of hypoglycaemia

Impaired awareness of hypoglycaemia (IAH), deﬁned either clinically as the loss of subjective awareness of hypoglycaemia before the onset of cognitive impairment or biochemically as the loss of symptom perception until plasma glucose has fallen below 3 mmol/L (54 mg/dl), is the major modiﬁable risk factor for severe hypoglycaemia in T1DM and possibly in insulin-treated T2DM. This paper tells the story of IAH, its pathogenesis and its implications and the treatment strategies used to address it.