Antibiotics and risk of subsequent first-time acute myocardial infarction

Context Increasing evidence supports the hypothesis of a causal association between certain bacterial infections and increased risk of developing acut e myocardial infarction. If such a causal association exists, subjects who used antibiotics active against the bacteria, regardless of indication, mig ht be at lower risk of developing acute myocardial infarction than nonusers . Objective To determine whether previous use of antibiotics decreases the ri sk of developing a first-time acute myocardial infarction, Design Population-based case-control analysis. Setting The United Kingdom-based General Practice Research Database compris ing 350 general practices. Patients A total of 3315 case patients aged 75 years or younger with a diag nosis of first-time acute myocardial infarction between 1992 and 1997 and 1 3139 controls without myocardial infarction matched to cases for age, sex, general practice attended, and calendar time. Main Outcome Measures Use of antibiotics among those who did or did not hav e a first-time acute myocardial infarction. Results Cases were significantly less likely to have used tetracycline anti biotics (adjusted odds ratio [OR], 0.70; 95% confidence interval [CI], 0.55 -0.90) or quinolones (adjusted OR, 0.45; 95% CI, 0.21-0.95). No effect was found for previous use of macrolides (primarily erythromycin), sulfonamides , penicillins, or cephalosporins. Conclusions The findings from this large case-control analysis provide furt her, albeit indirect, evidence for an association between bacterial infecti ons with organisms susceptible to tetracycline or quinolone antibiotics and the risk of acute myocardial infarction. These results of preliminary natu re should stimulate more research to further explore the role of infections in the etiology of acute myocardial infarction.