Cardiac Effects of Sulfonylurea-Related Hypoglycemia

• Published in: Diabetes care Vol. 40; no. 5; pp. 663 - 670
• Main Authors: Middleton, Timothy L, Wong, Jencia, Molyneaux, Lynda, Brooks, Belinda A, Yue, Dennis K, Twigg, Stephen M, Wu, Ted
• Format: Journal Article
• Language: English
• Published: United States 01.05.2017
• Subjects: Aged; Arrhythmias, Cardiac - physiopathology; Blood Glucose - metabolism; Diabetes Mellitus, Type 2 - drug therapy; Diabetes Mellitus, Type 2 - physiopathology; Electrocardiography, Ambulatory; Female; Heart - drug effects; Heart - physiopathology; Heart Rate - physiology; Humans; Hypoglycemia - blood; Hypoglycemia - chemically induced; Hypoglycemia - physiopathology; Hypoglycemic Agents - adverse effects; Hypoglycemic Agents - therapeutic use; Insulin - therapeutic use; Male; Middle Aged; Sulfonylurea Compounds - adverse effects; Sulfonylurea Compounds - therapeutic use
• ISSN: 0149-5992; 1935-5548
• DOI: 10.2337/dc16-1972

To determine the effect of sulfonylurea-related hypoglycemia on cardiac repolarization and ectopy in the setting of well-controlled type 2 diabetes. Thirty subjects with sulfonylurea-treated type 2 diabetes underwent 48 h of concurrent continuous glucose monitoring and ambulatory electrocardiography. Ventricular repolarization (QTc) and QT dynamicity were analyzed during periods of hypoglycemia (<3.5 mmol/L for >20 min) and compared with periods of euglycemia and hyperglycemia combined. Cardiac ectopy rates during hypoglycemia were compared with ectopy rates when blood glucose was 4-10 mmol/L. Mean HbA was 6.9% (52 mmol/mol). Hypoglycemia was detected in 9 of 30 subjects (30%); episodes were typically nocturnal (67%) and asymptomatic (73%). Hypoglycemia-associated QTc prolongation was seen in five of nine subjects with a large variation in individual response. Higher QT dynamicity, a poor prognostic factor in cardiac disease, was seen in subjects who experienced hypoglycemia compared with subjects who did not (0.193 vs. 0.159 for the nocturnal period; = 0.01). This finding persisted after the hypoglycemic event. The rates of ventricular and supraventricular ectopy demonstrated a nonsignificant trend toward an increase during hypoglycemia (median rate ratio 1.58 and 1.33, respectively). Similar, nonsignificant results were observed in a separate insulin-treated cohort. Hypoglycemia, often unrecognized, is a frequent finding in well-controlled sulfonylurea-treated type 2 diabetes. It is associated with the novel finding of increased QT dynamicity and QTc prolongation in some individuals. Our findings suggest sulfonylurea-related hypoglycemia can have detrimental cardiovascular sequelae. Similar effects are also seen in the setting of insulin therapy.