Myocardial infarction: no clear association with elevated C. pneumoniae IgG titres

Clinical bottom line (level 3b)

  1. Elevated Chlamydia pneumoniae IgG titres were not clearly associated with an increased risk of cardiovascular disease
Danesh et al: BMJ 2000; 321 : 208-213
Expires February 2004

The study

Case-control study with objective outcomes, adjusted for confounding factors, validated in an independent set of patients.

Setting: 24 towns, UK

1533 patients (aged mean 52, 100% male)
Cases: 502 patients (100% male, mean age 52): death from coronary heart disease or non-fatal myocardial infarction (based on WHO criteria)
Controls: 1029 patients (100% male, mean age 52): no myocardial infarction: matched for town, and age

Factors studied:
  • age, smoking, lipid levels, social class, martial status, father's occupation

    Factors summarised:
  • elevated IgG to C. pneumoniae: top third v. controls

    Outcomes studied:
  • cardiovascular death or non-fatal myocardial infarction

      The evidence

      Patient expected event rate for cardiovascular death or non-fatal myocardial infarction: 6.6%
      risk factor for
      cardiovascular death or non-fatal myocardial infarction       		adjusted OR
      (95% CI)      		 NNH
      (95% CI)
      elevated IgG to C. pneumoniae: 1.22
      (0.82 to 1.82)       		75
      (-90 to 21)

        Comments

        1. The authors also combined their study with 14 other cohort studies in a meta-analysis (not described in detail) and noted an odds ratio of 1.15 (95% CI: 0.95 to 1.41) with no significant heterogeneity.

        Citation

        1. Danesh J, Whincup P, Walker M, et al: Chlamydia pneumoiae IgG titres and coronary heart disease: prospective study and meta-analysis. BMJ 2000; 321 : 208-213
        Search Terms: from ACP Journal Club other articles noted
        Contributor: Chris Ball, February 2002
        Reviewer:

        Clinical Question.
        Patient male
        Intervention or Exposure seropositive for Chlamydia pneumoniae
        Outcome cardiovascular death or myocardial infarction