Severe hypoglycaemia in drug-treated diabetic patients needs attention: a population-based study

Objective

To study one-year incidence and risk factors of severe hypoglycaemias (SH) in adult drug-treated diabetic patients living in two Finnish communities.

Design

The episodes of SH and their risk factors were identified from local ambulance registers, from the databases of local health care units, and from patient questionnaires.

Setting

The target population consisted of all drug-treated diabetic patients from the two middle-sized communities in southern Finland, altogether 1776 patients. The study was retrospective.

Subjects

A total of 1469 patients (82.7% of the target population) gave informed consent for the use of their medical records and 1325 patients (74.6% of the target population) returned the detailed 36-item questionnaire.

Results

Of type 1 and type 2 insulin-treated diabetic patients, 14.6% and 1.0%, respectively, needed ambulance or emergency room care (incidence of 30.5 and 3.0 per 100 patient years). However, 31.0% of type 1 and 12.3% of type 2 diabetic patients reported at least one episode of SH (incidence of 72.0 and 27.0 per 100 patient years). Of all insulin-treated patients, 53 (7.8%) reported three or more episodes of SH. Significant independent risk factors for SH were depression, daily exercise, and nephropathy but not glycaemic control.

Conclusion

The incidence of SH was high in both types of insulin-treated diabetic patients. However, the recurrent episodes of SH were clustered in a small minority of insulin-treated patients with diabetes. The risk of SH should be considered when assessing the treatment target for an individual diabetic patient.Key Words: Insulin-treated diabetes, oral antidiabetic therapy, severe hypoglycaemia, type 1 diabetes, type 2 diabetesThe risk of severe hypoglycaemia (SH) has not been thought to be a problem in the treatment of type 2 diabetes.

• In this population-based study cohort severe hypoglycaemias in both type 1 and type 2 insulin-treated diabetic patients seemed to be more common than previously thought.
• Severe hypoglycaemias seem, however, to be clustered in a small minority of insulin-treated diabetic patients.
• The risk of severe hypoglycaemia should be considered when assessing the treatment target for an individual diabetic patient.

The risk of severe hypoglycaemias (SH) or the fear of them poses the greatest obstacle to achieving good glucose control in insulin-treated diabetic patients [1,2]. The population-based studies of the epidemiology of SH in patients with both type 1 and type 2 diabetes are quite limited and somewhat controversial [3–7]. Intensive antihyperglycaemic therapy and unawareness of hypoglycaemic symptoms increase the risk of SH in patients with type 1 diabetes [8–11], although this has not been the case in all studies [12,13].Recent prospective clinical trials with very intensive glucose lowering have also shown an increased risk of SH in patients with type 2 diabetes [14,15], although some clinical trials have suggested that the risk of SH is not a problem in insulin-treated patients with type 2 diabetes [16–19] and may be related to the insulin regimen used [7]. Use of sulphonylureas may increase the risk of SH, especially in old patients [7].In our retrospective population-based study we analysed the rate and risk factors of SH episodes, which were either self-reported or resulted in ambulance or emergency room care among diabetic residents of two Finnish communities during a one-year period.