title: High risk of abnormal QT prolongation in the early morning in diabetic and non-diabetic patients with severe hypoglycemia.
abstract: BACKGROUND
  Several studies have suggested that the occurrence of severe hypoglycemia during sleep may be more dangerous for cardiac arrhythmia than that in the day-time.
  
  
  METHODS
  We performed a retrospective study between January 2006 and March 2012 to assess electrocardiograms during severe hypoglycemia in patients with or without diabetes.
  
  
  RESULTS
  A total of 59,602 patients who visited the emergency room by ambulance were screened, and 287 patients with severe hypoglycemia were enrolled. The median blood glucose levels in patients with (DM, n = 192) and without diabetes (non-DM, n = 95) were 30 and 45 mg/dL, respectively. During severe hypoglycemia, the incidence of abnormal QT prolongation was significantly higher in the early morning (4-10 a.m.) than at other times (DM group, 74.3% versus 54.1%, P = 0.02; non-DM group, 78.3% versus 50.0%, P = 0.01). Multivariate logistic regression analysis identified the occurrence of severe hypoglycemia in the early morning as a strong factor for abnormal QT prolongation (DM group, odds ratio [OR] 2.80, 95% confidence interval [CI] 1.15-6.80, P = 0.02; non-DM group, OR 4.53, 95% CI 1.30-15.74, P = 0.01).
  
  
  CONCLUSIONS
  The incidence of abnormal QT prolongation during severe hypoglycemia was significantly higher in the early morning than at all other times, independent of the cause of severe hypoglycemia.
authors: Department of Diabetes, Endocrinology, and Metabolism, Center Hospital, National Center for Global Health and Medicine , Tokyo , Japan.
authors: Tetsuro
authors: T
authors: Tsujimoto
authors: Ritsuko
authors: R
authors: Yamamoto-Honda
authors: Hiroshi
authors: H
authors: Kajio
authors: Miyako
authors: M
authors: Kishimoto
authors: Hiroshi
authors: H
authors: Noto
authors: Remi
authors: R
authors: Hachiya
authors: Akio
authors: A
authors: Kimura
authors: Masafumi
authors: M
authors: Kakei
authors: Mitsuhiko
authors: M
authors: Noda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000097:blood / Q000503:physiopathology; D053840:Brugada Syndrome; D000075224:Cardiac Conduction System Disease; D057906:Circadian Clocks / Q000502:physiology; D016757:Death, Sudden, Cardiac; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006329:Heart Conduction System / Q000002:abnormalities / Q000503:physiopathology; D006801:Humans; D007003:Hypoglycemia / Q000097:blood / Q000503:physiopathology*; D008133:Long QT Syndrome / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012306:Risk
keywords: Arrhythmia; QT prolongation; diabetes; nocturnal hypoglycemia; severe hypoglycemia