Impaired awareness of hypoglycemia in a population-based sample of children and adolescents with type 1 diabetes

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. A validated questionnaire was administered to 656 patients with type 1 diabetes over a 6-month period to determine hypoglycemia awareness status. Case ascertainment was 79% of the clinic population. The rate of severe hypoglycemia was determined by data collected prospectively in the preceding year. 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), and had lower mean levels of A1C since diabetes onset (P = 0.006) and at their last visit (P = 0.001). The overall rate of severe hypoglycemia was 24.5 episodes per 100 patient-years in the preceding year. The severe hypoglycemia rate was higher in those with impaired awareness of hypoglycemia (37.1 vs. 19.3 episodes per 100 patient-years, P <0.001). Among patients aged