Recall of severe hypoglycaemia and self-estimated state of awareness in type 1 diabetes.

BACKGROUND: The ability of people with insulin-treated diabetes to remember severe hypoglycaemia and the consistency of their self-estimated awareness of hypoglycaemia are not well documented but are important in clinical practice. The aim of this study is to assess recall of severe hypoglycaemia in patients with type 1 diabetes and to evaluate the feasibility of a simple method for clinical classification of the awareness of hypoglycaemia.
METHODS: A one-year prospective study was performed on a cohort of patients with type 1 diabetes (n = 230). The rate of severe hypoglycaemia reported retrospectively at the end of the study was compared to the prospectively recorded rate during the study period. Self-estimated awareness was explored in questionnaires at baseline and at the end, and assessments were evaluated by the occurrence of severe hypoglycaemic episodes.
RESULTS: Almost 90% of the participants correctly recalled whether they had had severe hypoglycaemia. However, those with high prospectively recorded numbers had incomplete recall, resulting in a 15% underestimation of the overall rate. On the basis of the answer to the question "Do you recognise symptoms when you have a hypo?", the population was classified into three groups: 40% with normal awareness, 47% with impaired awareness and 13% with unawareness. The groups with impaired awareness and unawareness had 5.1 and 9.6 times higher rates of severe hypoglycaemia, respectively, compared to the group with normal awareness (p < 0.001).
CONCLUSION: People with type 1 diabetes generally remember severe hypoglycaemic episodes during a one-year period. A simple method is proposed for classifying the state of awareness of hypoglycaemia in clinical practice. Copyright 2003 John Wiley & Sons, Ltd.