Severe sulfonylurea-induced hypoglycemia: a problem of uncritical prescription and deficiencies of diabetes care in geriatric patients

Objective: Severe sulfonylurea-induced hypoglycemia (SH) remains a life-threatening and under-reported condition. We investigated the incidence of SH and clinical characteristics of patients with type 2 diabetes mellitus (T2DM) to demonstrate typical risk constellations. Methods: In a prospective population-based observational study, all consecutive cases of SH in the period 2000 - 2009 in a German area with 200,000 inhabitants were registered. Severe hypoglycemia was defined as a symptomatic event requiring treatment with intravenous glucose and was confirmed by a blood glucose measurement of < 50 mg/dl. Results: A mean incidence of seven episodes of SH per year and 100,000 inhabitants was registered. The 139 hypoglycemic individuals had been treated with glimepiride (n = 98), glibenclamide (n = 40) or gliquidone (n = 1). No preparation showed a constant dose-effect relationship, SH occurring within a wide dose range. The patients were characterized as follows: age 77.5 +/- 9.4 years, duration of diabetes 11 +/- 7 years, body mass index 26.3 +/- 4.9 kg/m(2), HbA1c 6.6 +/- 1.3%, creatinine clearance 46 +/- 24 ml/min with renal insufficiency in 73% and co-medication 7 +/- 3 drugs. Two-thirds of all subjects lived independently at home whereas a third were cared for by a home nursing service or received care in nursing homes. In all, 30% had participated in diabetes education programs. In 31%, systematic blood glucose monitoring was performed. Conclusions: Uncritical prescription of sulfonylureas neglecting crucial contraindications - particularly renal insufficiency - and deficiencies of diabetes care contributed substantially to the risk of SH in the mainly geriatric patients. There is a need for alternative therapeutic concepts that minimize the risk of hypoglycemia in geriatric patients with T2DM.