Risk of hospitalization for cardiovascular disease after use of macrolidesand penicillins: A comparative prospective cohort study

Chlamydia pneumoniae has been associated with cardiovascular diseases, and C. pneumoniae infection is treatable with macrolides. In this comparative c ohort study, 634 users of macrolides and 3827 users of penicillins were ide ntified from the Danish Health Service Registry of Prescriptions and follow ed up for an average of 6 months. The patients were then linked to the Regi onal Hospital Discharge Registry to assess the outcome of hospitalization f or cardiovascular disease. In the first 3 months, the relative risk (RR) of admission for a cardiovascular disease was 0.48 (95% confidence interval, 0.27-0.88) in users of macrolides compared with users of penicillins. No di fference was seen after 3 months. Interaction analyses indicated that the l ower risk seen in users of macrolides could be more pronounced in patients without versus those with a previous cardiovascular disease (RR, 0.39 vs. 0 .52), in patients greater than or equal to 60 versus <60 years old (RR, 0.3 9 vs. 0.64), and in men versus women (RR, 0.35 vs. 0.67).