| dc.description.abstract | Over one hundred years after the first doses of insulin were given as treatment for type 1 diabetes (TlD), hypoglycemia is still the main factor limiting optimal blood glucose control. Episodes of hypoglycemia are by itself one of the causes of reduced defense mechanisms towards hypoglycemia and the clinical syndrome of'impaired awareness of hypoglycemia' (IAH), defined as diminished or absent ability to recognize impending hypoglycemia. The syndrome is characterized by hypoglycemia being asymptomatic or that symptoms arise too late. A vicious circle with increased risk of severe hypoglycemia (SH) with loss of consciousness and need for help from others may then arise. Experiencing such episodes may lead to fear of hypoglycemia (FOH) with behaviors to keep blood glucose higher than recommended to avoid long-term complications of diabetes. The aim of this thesis of increased knowledge about IAH, also in children and adolescents, may as such contribute to better care, quality of life and health for those with diabetes.
In a cross-sectional study among adults with TlD in Central Norway, 445 (70% of those who were invited) responded to questionnaires about hypoglycemia. As expected, we found episodes of SH the previous year to be associated with increased FOH, but also that FOH to greater extent was associated with having IAH.
In our second study, we investigated whether two questionnaires often used to assess IAH in adults could be used also in children and adolescents. Children from two to nineteen years of age with TlD could participate, and 112 of those followed at the Children's Clinic at St. Olavs hospital in Trondheim completed these questionnaires (parents in children aged <9 years). They then kept a blood glucose diary for four weeks documenting details of all episodes of hypoglycemia. We found that the questionnaires possessed the most important measurement properties needed, and that those having IAH experienced more episodes of severe as well as clinically significant hypoglycemia, and more episodes without symptoms and where they did not recognize the hypoglycemia themselves. This is characteristic of the syndrome of IAH and we concluded that the questionnaires could be used in children and adolescents.
In the third study, we used these questionnaires in a nationwide survey to learn how prevalent IAH is in children and adolescents with TlD, and how those with IAH differ from those with normal hypoglycemia awareness. To investigate this we used data collected at annual controls registered in the Norwegian Childhood Diabetes Registry. Most clinics participated and we analyzed data from 1,329 participants, which is over half of the children and adolescents with TlD in Norway. We found that more than one out of five reported to have IAH, and this was more common the younger the child. Furthermore, it was more common in those who had experienced SH or DKA the previous year, in those with high FOH, in females and in those with the worst glycernic control.
The thesis concludes from these three studies that IAH, as assessed by these commonly used questionnaires, is prevalent also in children and adolescents with diabetes. Our fmdings further indicate that it is important to have knowledge of and assess IAH as it involves increased risk of SH and is related to FOH in both children and adults. | en_US |
