Background: Inflammation has been linked with atherosclerotic disease development and instability. Contributors to systemic inflammation, such as subclinical infection, may trigger acute coronary syndromes (ACSs).
Methods: Using a case-control study design, we evaluated the prevalence of urinary tract infection (UTI) among 100 consecutive ACS patients, compared with a contemporary control group undergoing elective coronary artery bypass graft (CABG) surgery. Cases were excluded if ACS was not confirmed by chart review or if a urinalysis was not obtained <or=6 hours of arrival. Patients excluded from the control group were those with myocardial infarction (MI) within 21 days before CABG or without a pre-CABG urinalysis.
Results: The case and control groups were well matched, with the only significant differences being less congestive heart failure (OR 7.3, 95% CI 3.3-15.9) and more prior MI (OR 0.5, 95% CI 0.3-0.9) in the CABG control group. UTI was present in 27 of the ACS cases and 11 of the controls. Among ACS case patients, those with UTI tended to be older and more often women, with more diabetes, hyperlipidemia, hypertension, and renal insufficiency, and more commonly had non-ST elevation MI. In unadjusted analysis, UTI was 3 times more common in the cases versus controls (OR 3.0, 95% CI 1.4-6.4); results were similar after multivariable adjustment (OR 3.0, 95% CI 1.3-6.8).
Conclusions: Subclinical UTI is common among patients with ACS. Underlying infection may precipitate ACS via activation of systemic inflammation. This hypothesis should be explored in other data sets, and similar relationships with other bacterial and viral infections should be examined.