An Evaluation of Methods of Assessing Impaired Awareness of Hypoglycemia in Type 1 Diabetes

Abstract

Subjective recognition of the warning symptoms of hypoglycemia is fundamental to allow self-treatment and prevent progression to severe hypoglycemia (1,2). Recognition of the onset of these premonitory symptoms constitutes awareness of hypoglycemia (3). With increasing duration of insulin therapy, many people with type 1 diabetes experience a change in their hypoglycemia awareness associated with either a reduction in symptom intensity or a change in symptom profile or both (3–6). Impaired awareness of hypoglycemia (IAH) is associated with a sixfold greater frequency of severe hypoglycemia and is a recognized risk factor for this problem (7,8). Accurate identification of individuals with IAH is important to allow modification of glycemic targets and to adjust insulin therapy to minimize hypoglycemia risk. Three methods have been proposed to assess awareness of hypoglycemia for clinical application (7–9) but to date have not been compared directly. The present study was performed in a randomly selected cohort of individuals with type 1 diabetes to assess the concordance between these methods in ascertaining the prevalence of IAH and whether the methods have equivalent sensitivity in identifying affected individuals. A total of 140 participants were recruited; 80 completed the study. Those who completed the study were significantly older than those who did not ( n = 60) (mean ± SD age 47.6 ± 12.7 vs. 41.1 ± 12.6 years, respectively, P = 0.04). No differences in duration of diabetes ( P = 0.7) or in glycemic control ( P = 0.35) were observed between these two groups. All completed a questionnaire to assess awareness of hypoglycemia using each of the methods presented by Gold et al. …