title: Role of socioeconomic status measures in long-term mortality risk prediction after myocardial infarction.
abstract: BACKGROUND
  The relationship of risk factors to outcomes has traditionally been assessed by measures of association such as odds ratio or hazard ratio and their statistical significance from an adjusted model. However, a strong, highly significant association does not guarantee a gain in stratification capacity. Using recently developed model performance indices, we evaluated the incremental discriminatory power of individual and neighborhood socioeconomic status (SES) measures after myocardial infarction (MI).
  
  
  METHODS
  Consecutive patients aged ≤65 years (N=1178) discharged from 8 hospitals in central Israel after incident MI in 1992 to 1993 were followed-up through 2005. A basic model (demographic variables, traditional cardiovascular risk factors, and disease severity indicators) was compared with an extended model including SES measures (education, income, employment, living with a steady partner, and neighborhood SES) in terms of Harrell c statistic, integrated discrimination improvement (IDI), and net reclassification improvement (NRI).
  
  
  RESULTS
  During the 13-year follow-up, 326 (28%) patients died. Cox proportional hazards models showed that all SES measures were significantly and independently associated with mortality. Furthermore, compared with the basic model, the extended model yielded substantial gains (all P<0.001) in c statistic (0.723 to 0.757), NRI (15.2%), IDI (5.9%), and relative IDI (32%). Improvement was observed both for sensitivity (classification of events) and specificity (classification of nonevents).
  
  
  CONCLUSIONS
  This study illustrates the additional insights that can be gained from considering the IDI and NRI measures of model performance and suggests that, among community patients with incident MI, incorporating SES measures into a clinical-based model substantially improves long-term mortality risk prediction.
authors.affiliation: Department of Epidemiology and Preventive Medicine, School of Public Health, Tel Aviv University, Israel.
authors.forename: Noa
authors.initials: N
authors.lastname: Molshatzki
authors.forename: Yaacov
authors.initials: Y
authors.lastname: Drory
authors.forename: Vicki
authors.initials: V
authors.lastname: Myers
authors.forename: Uri
authors.initials: U
authors.lastname: Goldbourt
authors.forename: Yael
authors.initials: Y
authors.lastname: Benyamini
authors.forename: David M
authors.initials: DM
authors.lastname: Steinberg
authors.forename: Yariv
authors.initials: Y
authors.lastname: Gerber
mesh_terms: D005260:Female; D006801:Humans; D007557:Israel / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality*; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D012959:Socioeconomic Factors