Clinical Question: Does antibiotic therapy prevent cardiovascular events in patients with heart disease?

Setting: Various (meta-analysis)

Study Design: Meta-analysis (randomized controlled trials)

Synopsis: The authors of this meta-analysis combined the results of nine randomized studies enrolling more than 11,000 participants (mostly men). They identified these studies by searching MEDLINE and references of review articles. They included in their analysis only articles written in English. The authors may have missed research findings: it is preferable to see a search of at least two databases, the inclusion of research in all languages, and a search for unpublished research. Their timing also may be poor: five large studies examining the role of antibiotic therapy in the prevention of cardiovascular events in patients with heart disease currently are being conducted.

The studies the authors used enrolled patients with known coronary heart disease who were treated with antibiotics regardless of the presence of Chlamydia pneumoniae. In the various studies, patients were treated with placebo or a macrolide antibiotic—azithromycin, roxithromycin, or clarithromycin—for seven to 90 days. The outcomes to be prevented were acute myocardial infarction, unstable angina, or sudden death. Individually, only one of the nine studies found a benefit to treatment; when combined, there was no statistically significant reduction in the combined outcomes or in mortality rates.

Bottom Line: In nine studies enrolling more than 11,000 participants with coronary heart disease, antibiotic treatment with a macrolide did not decrease the likelihood of death or a coronary event. More studies currently are being conducted in specific populations. (Level of Evidence: 1a)