Grayston JT et al. (2005) Azithromycin for the secondary prevention of coronary events. N Engl J Med 352: 1637–1645

Having established a link between Chlamydia pneumoniae infection and atherosclerosis, investigators have been prompted to ask whether antibiotic treatment might be beneficial in patients with coronary heart disease. Results of a recent US trial have shown, however, that treatment with azithromycin had no clinically significant effect on the risk of secondary cardiac events.

The Azithromycin and Coronary Events Study (ACES) included 4,012 patients with stable coronary heart disease. Participants were randomized in a 1:1 ratio to receive a weekly dose of azithromycin (600 mg) or placebo for 1 year.

During the mean follow-up period of 3.9 years, the primary endpoint (death due to coronary heart disease, coronary revascularization, nonfatal MI, or hospitalization for unstable angina) occurred in a similar proportion of patients in the treatment and placebo groups. The frequencies of each of the components of this endpoint were also similar in the two groups.

The authors comment that the trial was designed to study the effect of azithromycin treatment in patients with late-stage coronary heart disease only, and so the results do not exclude the possibility that C. pneumoniae is involved in the early development or progression of atherosclerosis. They conclude, however, that “antibiotic treatment cannot be recommended for the treatment of chronic coronary heart disease”.