[Incidence of severe hypoglycemia in relation to metabolic control and patient knowledge]

The question whether the incidence of severe episodes of hypoglycaemia in type I and type II diabetics correlates with the level of the patient's knowledge about hypoglycaemia and the quality of metabolic control.

A total of 234 consecutive type I diabetics (age and diabetes duration 48 and 16 years, respectively; blood glucose, self-monitored 63%) and 237 type II diabetics treated with glibenclamide (mean dose 6.7 mg/day) (age and diabetes duration 65 and 9 years, respectively; glucosuria, self-monitored 36%) who attended the Berlin outpatient diabetic centre were investigated.

Of the type I diabetics 23 (9.8%) experienced a total of 32 severe episodes of hypoglycaemia (incidence 0.14 per patient/year). Patients at risk of experiencing hypoglycaemia were about 20 years younger, injected insulin more often (3.8 vs 2.3 injections/day; p < 0.01) and had a lower HbA1 level (7.8% vs 9.0%; p < 0.01) than those having no hypoglycaemic reactions. Ten of the 23 diabetics suffering severe episodes of hypoglycaemia showed signs of kidney disease. The most common causes of hypoglycaemia were dietary errors (18.7%) or incorrect doses of insulin (12.5%), alcohol consumption (12.5%) and unusual physical exertion (23%). In terms of their knowledge about hypoglycaemia, there were no notably differences between patients with and those without hypoglycaemic reactions. Among the 237 type II diabetics treated with glibenclamide, three (1.3%) experienced one episode of severe hypoglycaemia each (incidence: 0.013 patient/year). Old age, maximum dosage of glibenclamide (15 mg/day) and multimorbidity were characteristic of these patients. Enquiries showed that only 49% (n = 160) of all type II diabetes had adequate knowledge about hypoglycaemia.

In type I diabetics, there appears to be no relationship between the hypoglycaemia risk and the patient's theoretical knowledge of hypoglycaemia. In future, apart from theoretical knowledge, more attention must be paid to practical training to improve awareness of hypoglycaemia. Educational programs for type II diabetics must attach more weight to the problem of hypoglycaemia.