title: Diabetes and Prior Coronary Heart Disease are Not Necessarily Risk Equivalent for Future Coronary Heart Disease Events.
abstract: BACKGROUND
  For more than a decade, the presence of diabetes has been considered a coronary heart disease (CHD) "risk equivalent".
  
  
  OBJECTIVE
  The objective of this study was to revisit the concept of risk equivalence by comparing the risk of subsequent CHD events among individuals with or without history of diabetes or CHD in a large contemporary real-world cohort over a period of 10 years (2002 to 2011).
  
  
  METHODS
  Population-based prospective cohort analysis.
  
  
  METHODS
  We studied a cohort of 1,586,061 adult members (ages 30-90 years) of Kaiser Permanente Northern California, an integrated health care delivery system.
  
  
  METHODS
  We calculated hazard ratios (HRs) from Cox proportional hazard models for CHD among four fixed cohorts, defined by prevalent (baseline) risk group: no history of diabetes or CHD (None), prior CHD alone (CHD), diabetes alone (DM), and diabetes and prior CHD (DM + CHD).
  
  
  RESULTS
  We observed 80,012 new CHD events over the follow-up period (~10,980,800 person-years). After multivariable adjustment, the HRs (reference: None) for new CHD events were as follows: CHD alone, 2.8 (95% CI, 2.7-2.85); DM alone 1.7 (95% CI, 1.66-1.74); DM + CHD, 3.9 (95% CI, 3.8-4.0). Individuals with diabetes alone had significantly lower risk of CHD across all age and sex strata compared to those with CHD alone (12.2 versus 22.5 per 1000 person-years). The risk of future CHD for patients with a history of either DM or CHD was similar only among those with diabetes of long duration (≥10 years).
  
  
  CONCLUSIONS
  Not all individuals with diabetes should be unconditionally assumed to be a risk equivalent of those with prior CHD.
authors.affiliation: Division of Cardiology, Kaiser Permanente Northern California, Oakland, CA, USA. jamal.s.rana@kp.org.|Department of Medicine, University of California San Francisco, San Francisco, CA, USA. jamal.s.rana@kp.org.|Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA. jamal.s.rana@kp.org.|Division of Cardiology, Kaiser Permanente Oakland Medical Center, Oakland, CA, USA. jamal.s.rana@kp.org.
authors.forename: Jamal S
authors.initials: JS
authors.lastname: Rana
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA.
authors.forename: Jennifer Y
authors.initials: JY
authors.lastname: Liu
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA.
authors.forename: Howard H
authors.initials: HH
authors.lastname: Moffet
authors.affiliation: Division of Endocrinology, Kaiser Permanente Medical Center, South San Francisco, CA, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Jaffe
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Karter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000453:epidemiology*; D003920:Diabetes Mellitus / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors
keywords: coronary heart disease; diabetes; epidemiology