Rates of hypoglycemia in users of sulfonylureas.

OBJECTIVE

To identify the demographic and clinical characteristics of sulfonylurea users. To assess the risk of hypoglycemia in patients treated with sulfonylureas in clinical practice, and to characterize the risk in relation to the different drugs used.

RESEARCH DESIGN AND METHODS

A cohort of 33,243 sulfonylurea users chosen from 719 clinical practices in the United Kingdom were identified through the VAMP-Research database. Information on demographic characteristics, medical diagnoses and use of medical services was obtained through the computerized records. For a stratified sample of 500 patients, general practioners completed a structured questionnaire on the duration, treatment, and complications of diabetes mellitus, obesity, alcohol use, and smoking history. Patients with a diagnosis of hypoglycemia, as recorded in the database within a time-window of a sulfonylurea prescription, were identified. Incidence rates per person-year of sulfonylurea therapy were estimated.

RESULTS

Other than a longer duration of diabetes in users of chlorpropamide, no differences were observed among users of different sulfonylurea agents with respect to diabetic complications, adequacy of diabetic control, obesity, smoking, and excessive alcohol consumption. A diagnosis of hypoglycemia during sulfonylurea therapy was recorded in 605 people over 34,052 person-years of sulfonylurea therapy, which converted into an annual risk of 1.8%. The risk in glibenclamide users was higher than in users of other types of sulfonylureas uses. Duration of therapy, concomitant use of insulin, sulfonylurea-potentiating or antagonizing and concomitant use of beta-blockers were predictive of the risk of developing hypoglycemia.

DISCUSSION

Drug use patterns showed comparability among users of different sulfonylurea agents. Our findings suggest that the rate of diagnosis of hypoglycemia made by physicians is higher for glibenclamide than for other sulfonylureas. An epidemiological study with objectively diagnosed hypoglycemia should be undertaken to confirm these results.