title: The effect of tobacco smoking and treatment strategy on the one-year mortality of patients with acute non-ST-segment elevation myocardial infarction.
abstract: BACKGROUND
  The aim of the present study was to investigate whether a previously shown survival benefit resulting from routine early invasive management of unselected patients with acute non-ST-segment elevation myocardial infarction (NSTEMI) may differ according to smoking status and age.
  
  
  METHODS
  Post-hoc analysis of a prospective observational cohort study of consecutive patients admitted for NSTEMI in 2003 (conservative strategy cohort [CS]; n = 185) and 2006 (invasive strategy cohort [IS]; n = 200). A strategy for transfer to a high-volume invasive center and routine early invasive management was implemented in 2005. Patients were subdivided into current smokers and non-smokers (including ex-smokers) on admission.
  
  
  RESULTS
  The one-year mortality rate of smokers was reduced from 37% in the CS to 6% in the IS (p < 0.001), and from 30% to 23% for non-smokers (p = 0.18). Non-smokers were considerably older than smokers (median age 80 vs. 63 years, p < 0.001). The percentage of smokers who underwent revascularization (angioplasty or coronary artery bypass grafting) within 7 days increased from 9% in the CS to 53% in the IS (p < 0.001). The corresponding numbers for non-smokers were 5% and 27% (p < 0.001). There was no interaction between strategy and age (p = 0.25), as opposed to a significant interaction between strategy and smoking status (p = 0.024). Current smoking was an independent predictor of one-year mortality (hazard ratio 2.61, 95% confidence interval 1.43-4.79, p = 0.002).
  
  
  CONCLUSIONS
  The treatment effect of an early invasive strategy in unselected patients with NSTEMI was more pronounced among smokers than non-smokers. The benefit for smokers was not entirely explained by differences in baseline confounders, such as their younger age.
authors.affiliation: Department of Cardiology, Vestfold Hospital Trust, Toensberg, Norway. erlend.aune@siv.no
authors.forename: Erlend
authors.initials: E
authors.lastname: Aune
authors.forename: Knut
authors.initials: K
authors.lastname: Endresen
authors.forename: Jo
authors.initials: J
authors.lastname: Roislien
authors.forename: Joran
authors.initials: J
authors.lastname: Hjelmesaeth
authors.forename: Jan Erik
authors.initials: JE
authors.lastname: Otterstad
mesh_terms: D000208:Acute Disease; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D009204:Myocardial Revascularization; D011379:Prognosis; D012307:Risk Factors; D012907:Smoking; D016019:Survival Analysis; D016896:Treatment Outcome