title: Baseline-Corrected QT (QTc) Interval Is Associated with Prolongation of QTc during Severe Hypoglycemia in Patients with Type 2 Diabetes Mellitus.
abstract: BACKGROUND
  We investigated an association between baseline heart rate-corrected QT (QTc) interval before severe hypoglycemia (SH) and prolongation of QTc interval during SH in patients with type 2 diabetes mellitus (T2DM).
  
  
  METHODS
  Between January 2004 and June 2014, 208 patients with T2DM, who visited the emergency department because of SH and underwent standard 12-lead electrocardiography within the 6-month period before SH were consecutively enrolled. The QTc interval was analyzed during the incidence of SH, and 6 months before and after SH. QTc intervals of 450 ms or longer in men and 460 ms or longer in women were considered abnormally prolonged.
  
  
  RESULTS
  The mean age and diabetes duration were 68.1±12.1 and 14.1±10.1 years, respectively. The mean QTc intervals at baseline and SH episodes were 433±33 and 460±33 ms, respectively (P<0.001). One hundred and fourteen patients (54.8%) had a prolonged QTc interval during SH. There was a significant decrease in the prolonged QTc interval within 6 months after SH (QTc interval prolongation during SH vs. after recovery, 54.8% vs. 33.8%, P<0.001). The prolonged QTc interval was significantly associated with baseline QTc interval prolongation (odds ratio, 2.92; 95% confidence interval, 1.22 to 6.96; P=0.016) after adjusting for multiple confounders.
  
  
  CONCLUSIONS
  A prolonged QTc interval at baseline was significantly associated with prolongation of the QTc interval during SH in patients with T2DM, suggesting the necessity of QTc interval monitoring and attention to those with a prolonged QTc interval to prevent SH.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Seon Ah
authors.initials: SA
authors.lastname: Cha
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Yun
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Tae Seok
authors.initials: TS
authors.lastname: Lim
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Yoon Goo
authors.initials: YG
authors.lastname: Kang
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Kang Min
authors.initials: KM
authors.lastname: Lee
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Ki Ho
authors.initials: KH
authors.lastname: Song
authors.affiliation: Division of Cardiology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Ki Dong
authors.initials: KD
authors.lastname: Yoo
authors.affiliation: Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA.
authors.forename: Yong Moon
authors.initials: YM
authors.lastname: Park
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Ko
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea. ybahn@catholic.ac.kr.
authors.forename: Yu Bae
authors.identifier: http://orcid.org/0000-0001-8658-2731
authors.initials: YB
authors.lastname: Ahn
keywords: Diabetes mellitus, type 2; QT interval; Severe hypoglycemia