Comparison of hypoglycemia perception and hormonal counterregulation in controlled hypoglycemia. A contribution to diagnosis of hypoglycemia unawareness syndrome in type 1 diabetic patients

Diabetics with abnormal hypoglycaemia awareness cannot recognize hypoglycaemic symptoms early and adequately enough to respond, thus endangering in everyday life not only themselves but also others. Thus it is important to diagnose such symptoms early and assess the extent to which the diabetic is at risk of severe hypoglycaemia. This study was designed to contribute to the evaluation of hypoglycaemia awareness in type 1 (IDDM) diabetics.In 57 diabetics (IDDM) awareness of typical hypoglycaemic warning symptoms and of hormonal counterregulation were tested during controlled induced hypoglycaemia. A questionnaire was used to measure at fixed time intervals, along a four-point scale, the severity of 6 autonomic and 6 cerebral warning symptoms, and compare them with synchronously obtained plasma levels of glucagon and epinephrine.The cohort was divided into three groups according to the rise of epinephrine levels induced by the hypoglycaemia. Group A (n = 22) showed a significant rise in epinephrine level at the onset of hypoglycaemia; group B (n = 22): significantly increased epinephrine only after 30 min of hypoglycaemia; group C (n = 15): no epinephrine rise at any time during hypoglycaemia. None of the patients had a significant rise in glucagon levels. There were significant differences between the three groups regarding HbA1c levels and the duration of diabetes. Low levels of HbA1c and duration of diabetes were commonly associated with a loss of hormonal counterregulation. In only 40% of patients was it possible to draw any conclusion about epinephrine-induced hypoglycaemia from symptoms revealed in the past history.The past history of hypoglycaemic symptoms is an unreliable and inadequate guide for objectively assessing the actual risk of hypoglycaemia in type 1 diabetics. The results of this study indicate that when severe hypoglycaemic attacks (requiring outside help etc.) are suspected, standardized diagnostic tests of hypoglycaemia awareness should be performed in specialized centres, particularly if an official medical report ist required.