Chlamydia pneumoniae and future risk in patients with coronary heart disease

Aim: To evaluate the association between previous exposure to Chlamydia pneumoniae and future coronary risk in patients with coronary heart disease. Methods: A prospective, nested, case-control design was used. The patient sample was derived from a trial study of bezafibrate for the treatment of coronary heart disease. Anti-Chlamydia pneumoniae antibodies (IgG and IgA) in the baseline sera of 136 patients who had coronary events during follow-up (mean 6.2 years) were compared with those in 136 age- and gender-matched patients from the same trial without subsequent coronary events. Results: Mean titers of IgG and IgA antibodies were similar in cases and controls. The relative odds of future coronary events in patients who were seropositive at baseline were 1.0 (95% CI, 0.54–1.84) for IgG and 0.74 (95% CI, 0.41–1.31) for IgA. The relative odds did not change after adjustment for multiple confounding variables. The risk of future coronary events did not increase with increasing anti-Chlamydia pneumoniae antibody titers. Conclusions: Prior exposure to Chlamydia pneumoniae in patients with chronic coronary heart disease is not associated with increased risk of recurrent coronary events.