Serious Hypoglycemia at Both High and Low Glycosylated Hemoglobin Levels

In a study published in 2013, serious hypoglycemia was associated with both high (>9%) and low (<6%) levels of glycosylated hemoglobin (HbA_1c) in patients with type 2 diabetes — a so-called U-shaped association (NEJM JW Gen Med Jan 15 2014 and Diabetes Care 2013; 36:3535). Now, another research group has examined this issue.

U.K. researchers identified 304 patients with type 2 diabetes who had a first hospitalization for severe hypoglycemia and underwent HbA_1c testing within the previous 90 days. These cases were compared with 304 controls — matched by age, sex, duration of diabetes, and other relevant clinical characteristics — who were not hospitalized for hypoglycemia. Compared with HbA_1c of 7.0%, HbA_1c levels of 6% and 9% conferred exces…