BACKGROUND: Given the premise that certain bacteria (such as Chlamydia pneumoniae) may play a role in the etiology of atherosclerosis, subjects treated with antibiotics that have antibacterial activity against C pneumoniae may be at lower risk for the development of an acute myocardial infarction (MI) than untreated subjects. METHODS: A case-control design, nested within a cohort of 29,937 elderly subjects in whom antihypertensive therapy was initiated (1982-1995) was used, in which each subject who was hospitalized with a primary discharge diagnosis of MI between 1987 and 1995 (n = 1047) was matched on calendar time to 5 randomly selected control subjects for exposure contrasts. Conditional logistic regression analyses were conducted to adjust for predisposing factors for MI. RESULTS: Although no clear consistent effect of antibiotics use was found in relation to MI, a trend was observed for a decreased risk of acute MI in patients receiving a prescription for antichlamydial antibiotics in the preceding 3 months (odds ratio 0.68, 95% CI 0.46-1.00). Antibiotics without antichlamydial activity showed no benefit in MI risk. CONCLUSION: The beneficial effect of certain antichlamydial antibiotics in reducing the risk of MI cannot be excluded on the basis of this representative cohort of elderly patients in a routine clinical care setting. Larger prospective studies are required to confirm the usefulness of antibiotics in the primary prevention of MI.
BACKGROUND: Given the premise that certain bacteria (such as Chlamydia pneumoniae) may play a role in the etiology of atherosclerosis, subjects treated with antibiotics that have antibacterial activity against C pneumoniae may be at lower risk for the development of an acute myocardial infarction (MI) than untreated subjects. METHODS: A case-control design, nested within a cohort of 29,937 elderly subjects in whom antihypertensive therapy was initiated (1982-1995) was used, in which each subject who was hospitalized with a primary discharge diagnosis of MI between 1987 and 1995 (n = 1047) was matched on calendar time to 5 randomly selected control subjects for exposure contrasts. Conditional logistic regression analyses were conducted to adjust for predisposing factors for MI. RESULTS: Although no clear consistent effect of antibiotics use was found in relation to MI, a trend was observed for a decreased risk of acute MI in patients receiving a prescription for antichlamydial antibiotics in the preceding 3 months (odds ratio 0.68, 95% CI 0.46-1.00). Antibiotics without antichlamydial activity showed no benefit in MI risk. CONCLUSION: The beneficial effect of certain antichlamydial antibiotics in reducing the risk of MI cannot be excluded on the basis of this representative cohort of elderly patients in a routine clinical care setting. Larger prospective studies are required to confirm the usefulness of antibiotics in the primary prevention of MI.