title: Heart rate-corrected QT interval is an independent predictor of all-cause and cardiovascular mortality in individuals with type 2 diabetes: the Diabetes Heart Study.
abstract: OBJECTIVE
  Heart rate-corrected QT (QTc) interval is associated with mortality in the general population, but this association is less clear in individuals with type 2 diabetes. We assessed the association of QTc interval with all-cause and cardiovascular disease (CVD) mortality in the Diabetes Heart Study.
  
  
  METHODS
  We studied 1,020 participants with type 2 diabetes (83% European Americans; 55% women; mean age 61.4 years) who were free of atrial fibrillation, major ventricular conduction defects, and antiarrhythmic therapy at baseline. QT duration was automatically calculated from a standard 12-lead electrocardiogram (ECG). Following American Heart Association/American College of Cardiology Foundation recommendations, a linear scale was used to correct the QT for heart rate. Using Cox regression, risk was estimated per 1-SD increase in QTc interval as well as prolonged QTc interval (>450 ms) vs. normal QTc interval for mortality.
  
  
  RESULTS
  At baseline, the mean (SD) QTc duration was 414.9 ms (18.1), and 3.0% of participants had prolonged QTc. After a median follow-up time of 8.5 years (maximum follow-up time 13.9 years), 204 participants were deceased. In adjusted multivariate models, a 1-SD increase in QTc interval was associated with an 18% higher risk for all-cause mortality (hazard ratio 1.18 [95% CI 1.03-1.36]) and 29% increased risk for CVD mortality (1.29 [1.05-1.59]). Similar results were obtained when QTc interval was used as a categorical variable (prolonged vs. normal) (all-cause mortality 1.73 [0.95-3.15]; CVD mortality 2.86 [1.35-6.08]).
  
  
  CONCLUSIONS
  Heart rate QTc interval is an independent predictor of all-cause and CVD mortality in this population with type 2 diabetes, suggesting that additional prognostic information may be available from this simple ECG measure.
authors.affiliation: Corresponding author: Donald W. Bowden, dbowden@wakehealth.edu.
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Cox
authors.forename: Amir
authors.initials: A
authors.lastname: Azeem
authors.forename: Joseph
authors.initials: J
authors.lastname: Yeboah
authors.forename: Elsayed Z
authors.initials: EZ
authors.lastname: Soliman
authors.forename: Shivani R
authors.initials: SR
authors.lastname: Aggarwal
authors.forename: Alain G
authors.initials: AG
authors.lastname: Bertoni
authors.forename: J Jeffrey
authors.initials: JJ
authors.lastname: Carr
authors.forename: Barry I
authors.initials: BI
authors.lastname: Freedman
authors.forename: David M
authors.initials: DM
authors.lastname: Herrington
authors.forename: Donald W
authors.initials: DW
authors.lastname: Bowden
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000401:mortality / Q000503:physiopathology; D053840:Brugada Syndrome; D000075224:Cardiac Conduction System Disease; D002318:Cardiovascular Diseases / Q000401:mortality* / Q000503:physiopathology; D002423:Cause of Death; D003924:Diabetes Mellitus, Type 2 / Q000401:mortality* / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000002:abnormalities / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012306:Risk; D012307:Risk Factors; D014481:United States