Myocardial infarction: continuing to smoke increased the risk of death or reinfarction.

Clinical bottom line (level 1b)

  1. One in four men with a first myocardial infarction died within 10 years. One in four had another myocardial infarction within 10 years.
  2. Continuing to smoke increased this risk even further (RR = 1.5)
Aberg et al: British Heart Journal 1983; 49: 416-422
Expires March 2003

The study

Prospective cohort study with objective outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: community, Sweden

983 patients (aged under 67, 100% male) with a first myocardial infarction

Excluded if
  • smoking status could not be determined
  • died before discharge from hospital



    • Factors studied:
  • smoking, age, severity of infarction
  • continued to smoke at least one cigarette a day
  • continued to smoke at least one cigarette a day




    • A logistic regression analysis was used to adjust for confounding factors.

    ?100% followed for up to 10 years
    Outcomes studied:
  • non-fatal myocardial infarction
  • death

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)    		 NNF
    (95% CI)
    non-fatal myocardial infarction 10 years 231/983 24%
    (21% to 26%)    		 4
    (4 to 5)
    death up to 10 years 223/983 23%
    (20% to 25%)    		 4
    (4 to 5)

    prognostic factor for
    non-fatal myocardial infarction     		time to outcome unadjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    continued to smoke up to 10 years 1.50
    (1.45 to 1.56)     		10
    (6 to 27)

    prognostic factor outcome present outcome absent unadjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    continued to smoke 127 314 1.50
    (1.45 to 1.56)     		10
    (6 to 27)
    no continued to smoke 104 438

    prognostic factor for
    death     		time to outcome unadjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    continued to smoke up to 10 years 1.60
    (1.26 to 2.02)     		9
    (6 to 21)

    prognostic factor outcome present outcome absent unadjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    continued to smoke 126 315 1.60
    (1.26 to 2.02)     		9
    (6 to 21)
    no continued to smoke 97 445

    • Smoking was independently associated with death and reinfarction, but no adjusted relative risks were provided.

    Comments

    1. Absolute values are probably lower today, with more routine use of ACE-inhibitors, statins and aggressive revascularisation interventions.

    Citation

    1. Aberg A, Bergstrand R, Johansson Saga, et al: Cessation of smoking after myocardial infarction: effects on mortality after 10 years. British Heart Journal 1983; 49: 416-422
    Search Terms: smok* and infarct* in PubMed
    Contributor: Chris Ball and Clare Wotton, February 2000
    Reviewer: Urs Glenck

    Clinical Question.
    Patient first myocardial infarction, smoking
    Intervention or Exposure stopped smoking
    Outcome death, myocardial infarction