title: Development and validation of a prognostic index for risk stratification of patients with early repolarization.
abstract: BACKGROUND
  Early repolarization (ER) is associated with increased mortality in the general population. We sought to develop and validate a prognostic index (PI) of mortality in patients with ER.
  
  
  METHODS
  We identified 852 consecutive patients (mean age 49 ± 12 years) with ER (J-point elevation ≥0.1 mV in inferior or lateral leads), from the VA electronic electrocardiogram (ECG) database. A random sample of age-matched patients with normal ECG was used as control (n = 257). The initial cohort was randomly split into a derivation and a validation cohort (2/3 and 1/3 of patients, respectively). A PI was derived from the weighed sum of the regression coefficients of each independent risk factor in the final model using Cox regression analysis.
  
  
  RESULTS
  During a median follow-up of 6.4 years, 170 patients died. ER was associated with increased mortality compared to control (HR 1.49, 95% CI 1.05-2.12; P = 0.03). Older age, lower body mass index, non-African American race, current use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers or sulfonyureas, prolonged corrected QT (QTc), and higher ER amplitude independently predicted all-cause mortality. Annualized mortality rates were 1.3%, 2.2%, and 3.7% in the low, intermediate, and high-risk groups, respectively, in the derivation cohort (log rank P < 0.0001) and 0.8%, 1.9%, and 4.1% in the low, intermediate, and high-risk groups, respectively, in the validation cohort (log rank P < 0.0001). Model discrimination was very good (c-statistic = 0.85 and 0.80 for derivation and validation cohort, respectively).
  
  
  CONCLUSIONS
  A PI derived from simple clinical and ECG characteristics predicts mortality in patients with ER and may be used clinically for risk stratification.
authors.affiliation: Department of Medicine Cardiovascular Section Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA. stavros-stavrakis@ouhsc.edu
authors.forename: Stavros
authors.initials: S
authors.lastname: Stavrakis
authors.forename: Nishit
authors.initials: N
authors.lastname: Patel
authors.forename: Charles
authors.initials: C
authors.lastname: Te
authors.forename: Harsh
authors.initials: H
authors.lastname: Golwala
authors.forename: Augustine
authors.initials: A
authors.lastname: George
authors.forename: Pedro
authors.initials: P
authors.lastname: Lozano
authors.forename: Ralph
authors.initials: R
authors.lastname: Lazzara
mesh_terms: D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000503:physiopathology; D015331:Cohort Studies; D004562:Electrocardiography / Q000379:methods / Q000706:statistics & numerical data*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors