Prevalence and risk factors of prolonged QTc interval in type 2 diabetic patients; impact of the type of treatment and quality of glycemic control

Abstract

Introduction: A prolonged heart rate-adjusted QT (QTc) interval is considered a risk factor for malignant arrhythmias and sudden cardiac death. The aim of this study was to assess the prevalence and predictors of prolonged QTc interval in patients with type 2 diabetes (T2D). Methods: This study included 501 T2D patients treated in National Educational Centre for Diabetes, Specialistic Hospital (SH) “Merkur”, Vrnjacka Banja, Serbia, from September 2011 to July 2012 (table 1). We analysed baseline clinical and laboratory data including: age, gender, duration of diabetes, body mass index, presence of coronary artery disease (CAD), presence of polyneuropathy, type of treatment, renal function, and the presence of traditional risk factors for CAD. In all patients 6-8 blood samples were taken within 24 h and following parameters of glycoregulation were analysed: fasting blood glucose (FBG), mean value of blood glucose (MBG), and mean amplitude of glucose excursion (MAGE), as well as HbA1c (table 2). In baseline ECG QT interval was measured using digital ruler. Heart rate corrected QT interval (QTc) was calculated using Bazett’s formula, considering QTc> 440 msec as prolonged, and QTc> 500 msec as significantly prolonged.