Hypoglycaemia in Insulin-treated Type 2 Diabetes: Frequency, Symptoms and Impaired Awareness

Aims: Hypoglycaemia is considered to be less common in people with insulin-treated Type 2 diabetes than in Type 1 diabetes. A retrospective survey was made of 215 people with insulin-treated Type 2 diabetes to quantify the frequency and nature of hypoglycaemia experienced.

Methods: The frequencies of mild (self-treated) and severe (required assistance) hypoglycaemia during the preceding year were estimated retrospectively. The usual symptoms of hypoglycaemia and state of awareness of hypoglycaemia were scored using validated questionnaires and any history suggestive of impaired hypoglycaemia awareness was documented.

Results: In this cohort, 157 (73%) had experienced hypoglycaemia since commencing insulin, the frequency of which increased with duration of diabetes and of insulin therapy and was inversely related to current HbA1c (all P < 0.05). During the preceding year, 32 individuals (15%) had experienced severe hypoglycaemia, with an estimated incidence for the entire group of 0.28 episodes/patient/year. Principal components analysis revealed two underlying symptom groups (autonomic and neuroglycopenic), similar to those reported previously by young adults with Type 1 diabetes, but the total symptom score declined with advancing age. Of the 157 with a history of hypoglycaemia, the 13 (8%) individuals who gave a history of impaired awareness of hypoglycaemia had experienced a ninefold higher incidence of severe hypoglycaemia than those with normal awareness, and reported experiencing mainly neuroglycopenic symptoms.

Conclusions: While the overall frequencies of mild and severe hypoglycaemia were lower in insulin-treated Type 2 diabetes than have been reported previously in Type 1 diabetes, the risk of hypoglycaemia was greater with increasing duration of diabetes and of insulin therapy. Although impaired awareness of hypoglycaemia was uncommon, it was associated with a higher incidence of severe hypoglycaemia.