Hypoglycemia in adults with Type 1 Diabetes Mellitus: Investigating symptoms and awareness of hypoglycemia and the association between impaired awareness of hypoglycemia, autonomic neuropathy and cognition

Abstract

Hypoglycemia is still the main limitation for the management of Type 1 diabetes mellitus (T1DM). If it were not for hypoglycemia, treatment of T1DM would be easy. Subjects with T1DM have impaired defense mechanisms against hypoglycemia; this makes them dependent on symptoms in order to detect a hypoglycemic episode and take appropriate action to restore blood glucose levels. Impaired awareness of hypoglycemia (IAH) is a reduced ability to perceive the onset of hypoglycemia. Subjects with IAH thereby have increased risk for development of severe hypoglycemia. We wanted to investigate the symptomatology of hypoglycemia in relation to diabetes duration. In addition, we wanted to investigate if symptom intensity is associated with IAH. We found that lower autonomic symptom intensity and a predominance neuroglycopenic symptoms, is associated with longer diabetes duration. We found IAH to be associated with higher overall- and higher neuroglycopenic symptom intensity, but not with lower autonomic symptom intensity. Activation of the autonomic nervous system is important for counterregulation during hypoglycemia. Although results of previous studies have not been convincing of such an association, it has almost been regarded as an unwritten truth that autonomic neuropathy contributes to the development of IAH. We therefore found it appropriate to investigate this hypothesis. We did not find any association between IAH and autonomic neuropathy. Cognitive impairment is getting increasing recognition as a complication of T1DM. It is likely that cognitive impairment affects diabetes self-management. We wanted to investigate if cognitive impairment is associated with IAH. We found IAH to be associated with impaired memory, learning, pattern separation and possibly also executive function.