BACKGROUND

Infection with Helicobacter pylori and Chlamydia pneumoniae is associated with coronary heart disease. We conducted an intervention study using antibiotics against these bacteria in patients with acute coronary syndromes to determine whether antibiotics reduce inflammatory markers and adverse cardiac events.

RESULTS

Patients (n=325) admitted with acute myocardial infarction or unstable angina (acute coronary syndromes) were randomized to receive a 1-week course of 1 of 3 treatment regimens: (1) placebo; (2) amoxicillin (500 mg twice daily), metronidazole (400 mg twice daily), and omeprazole (20 mg twice daily); or (3) azithromycin (500 mg once daily), metronidazole (400 mg twice daily), and omeprazole (20 mg twice daily). Serum fibrinogen, white cell count, and high-sensitivity C-reactive protein were measured at study entry and at 1, 3, and 12 months during follow-up. Cardiac death and readmission with acute coronary syndrome were considered clinical end points. Patients were followed for 1 year. C-reactive protein levels were reduced (P=0.03) in unstable angina patients receiving amoxicillin, and fibrinogen was reduced in both patient groups receiving antibiotics (P=0.06). There were 17 cardiac deaths and 71 readmissions with acute coronary syndrome. No difference in frequency or timing of end points was observed between the 2 antibiotic groups. At 12 weeks, there was a 36% reduction in all end points in patients receiving antibiotics compared with placebo (P=0.02). This reduction persisted during the 1-year follow-up. Neither C pneumoniae nor H pylori antibody status was significantly related to response to treatment.

CONCLUSIONS

Antibiotic treatment significantly reduced adverse cardiac events in patients with acute coronary syndromes, but the effect was independent of H pylori or C pneumoniae seropositivity.