A meta-analysis of antibiotic use for the secondary prevention of cardiovascular diseases.

backgroundA number of clinical trials have examined whether antibiotics decrease the incidence of adverse events in patients with cardiovascular diseases. However, results have occasionally been conflicting, and a meta-analysis may provide additional clarification.

objectiveTo address whether antibiotic use can reduce the risk of future cardiac events among patients with established cardiovascular diseases.

methodsPubMed and the Cochrane Central Register of Controlled Trials were searched using the key words "antibiotic" and "cardiovascular diseases". Only randomized, placebo-controlled trials of patients with established cardiovascular disease and reporting cardiovascular outcomes were included. A random effects model was used and a fixed model was applied for sensitivity analysis.

resultsA total of 393 papers published between January 1, 1994, and April 31, 2006, were initially identified. Thirteen trials (12,491 patients in the treatment group and 12,518 patients in the control group) were retained and included in the present meta-analysis. The pooled RR for the composite event end point, including death, myocardial infarction admission and unplanned revascularization procedures, was 0.96 (95% CI 0.90 to 1.04). No associations were seen for the individual outcomes of mortality (RR 1.07, 95% CI 0.96 to 1.19) or myocardial infarction/unstable angina (RR 0.96, 95% CI 0.85 to 1.07). Subgroup analyses based on patient populations (stable or unstable), type of antibiotics, or restricted to those with immunoglobulin G Chlamydia pneumoniae antibodies were also negative for a beneficial treatment effect. Similar results were found using a fixed effects model.

conclusionsThe meta-analysis did not provide evidence of an association between antibiotic use and the secondary prevention of cardiac events. Further research in this area does not appear to be promising.