title: Risk factor and prediction modeling for sudden cardiac death in women with coronary artery disease.
abstract: BACKGROUND
  To our knowledge, the risk of sudden cardiac death (SCD) and the assessment of risk factors in prediction models have not been evaluated in women with coronary artery disease (CAD). We sought to evaluate the incidence of SCD as well as its risk factors and their predictive accuracy among a population of women with CAD.
  
  
  METHODS
  The Heart and Estrogen/progestin Replacement Study evaluated the effects of hormone replacement therapy on cardiovascular events among 2763 postmenopausal women with CAD. Sudden cardiac death was defined as death resulting from a cardiac origin that occurred within 1 hour of symptom onset. The associations between candidate predictor variables and SCD were evaluated in a Cox proportional hazards model. The C-index was used to compare the predictive value of the clinical risk factors with left ventricular ejection fraction (LVEF) alone and in combination. The net reclassification improvement was also computed.
  
  
  RESULTS
  Over a mean follow-up of 6.8 years, SCD comprised 136 of the 254 cardiac deaths. The annual SCD event rate was 0.79% (95% confidence interval, 0.67-0.94). The following variables were independently associated with SCD in the multivariate model: myocardial infarction, heart failure, an estimated glomerular filtration rate of less than 40 mL/min/1.73 m(2), atrial fibrillation, physical inactivity, and diabetes. The incidences of SCD among women with 0 (n = 683), 1 (n = 1224), 2 (n = 610), and 3 plus (n = 246) risk factors at baseline were 0.3%, 0.5%, 1.2%, and 2.9% per year, respectively. The combination of clinical risk factors and LVEF (C-index, 0.681) were better predictors of SCD than LVEF alone (C-index, 0.600) and resulted in a net reclassification improvement of 0.20 (P < .001).
  
  
  CONCLUSIONS
  Sudden cardiac death comprised the majority of cardiac deaths among postmenopausal women with CAD. Independent predictors of SCD, including myocardial infarction, congestive heart failure, an estimated glomerular filtration rate of less than 40 mL/min/1.73 m(2), atrial fibrillation, physical inactivity, and diabetes, improved SCD prediction when they were considered in addition to LVEF.
authors.affiliation: Section of Electrophysiology, Division of Cardiovascular Medicine, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA. Rajat.Deo@uphs.upenn.edu
authors.forename: Rajat
authors.initials: R
authors.lastname: Deo
authors.forename: Eric
authors.initials: E
authors.lastname: Vittinghoff
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.forename: Zian H
authors.initials: ZH
authors.lastname: Tseng
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Hulley
authors.forename: Michael G
authors.initials: MG
authors.lastname: Shlipak
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000401:mortality; D003324:Coronary Artery Disease / Q000150:complications / Q000401:mortality* / Q000503:physiopathology; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000209:etiology*; D048909:Diabetes Complications / Q000401:mortality; D015914:Estrogen Replacement Therapy; D005260:Female; D005919:Glomerular Filtration Rate; D006333:Heart Failure / Q000401:mortality; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity; D015337:Multicenter Studies as Topic; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000401:mortality; D017698:Postmenopause; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D014481:United States / Q000453:epidemiology