Abstract

Objective: To determine the prevalence and clinical associations of impaired awareness of hypoglycemia in a population-based sample of children and adolescents with type 1 diabetes.

Research Design and Methods: A validated questionnaire was administered to 656 patients with type 1 diabetes over a six-month period to determine hypoglycemia awareness status. Case ascertainment was 79% of the clinic population. The rate of severe hypoglycemia (SH) was determined by data collected prospectively in the preceding year.

Results: Impaired awareness of hypoglycemia was present in 29% of patients. Patients with impaired awareness of hypoglycemia had an earlier onset of diabetes (p<0.001), were younger (p<0.001), had lower mean levels of A1C since diabetes onset (p=0.006) and at their last visit (p=0.001). The overall rate of SH was 24.5 episodes/100 patient-years, in the preceding year. The SH rate was higher in those with impaired awareness of hypoglycemia (37.1 vs. 19.3 episodes/100 patient-years, p<0.001). Among patients aged below 6 years (n=46), 59% of care providers reported impaired awareness of hypoglycemia and the rate of SH was significantly higher in those reporting impaired awareness (33.3 vs. 5.2 episodes/100 patient-years, p=0.02). More patients with recurrent hypoglycemia reported impaired awareness of hypoglycemia (47% vs 28%, p=0.03).

Conclusions: A significant proportion of children and adolescents with type 1 diabetes have impaired awareness of hypoglycemia. Screening for impaired awareness is an important component of routine diabetes care and can identify patients at increased risk of a severe hypoglycemic event.