[Nocturnal hypoglycemia with reference to hormonal counterregulation in type I diabetics receiving insulin therapy]

Frequency, symptomatology and risk factors for nocturnal hypoglycemia were investigated in 77 type 1 diabetics. The patients were hospitalized overnight after a normal working day and were kept on their usual insulin regimen. Nocturnal blood sugar levels less than 2.8 mmol/l were found in 25% of 77 patients. In most cases the hypoglycemic event was not noticed by the patients. Additionally, nocturnal hormonal counterregulations were investigated in 22 patients. Plasma adrenalin, noradrenalin, somatotropin, cortisol and glucagon were measured every 2 hours. Although most of the patients were asymptomatic, a significant increase in plasma adrenalin was observed during hypoglycemia episodes. On the other hand, the increase in noradrenalin and somatotropin concentration was not significant. Blood sugar levels of 5 mmol/l and lower at 22 p.m. and at 7 a.m. (as well as diabetes duration) were identified as risk factors for nocturnal hypoglycemia. Nocturnal hypoglycemia occurs irrespective of the amount of insulin injected in the evening or at bedtime. Similarly, neither the time of late insulin injection nor the degree of metabolic control as assessed by HbA1c differed in patients undergoing hypoglycemic episodes and patients without hypoglycemia.