Acute Myocardial Infarction and Community-acquired Staphylococcus aureus Bloodstream Infection: An Observational Cohort Study

Background: The relationship between acute myocardial infarction and infection was recognized in the early 20th century during influenza epidemics. Most recently, a case control study and a self-control design study have identified an association between Staphylococcus aureus infection and acute myocardial infarction. We assessed the association of community-acquired Staphylococcus aureus bloodstream infection (CA-SABSI) and myocardial infarction in the 365 days following blood culture. Methods: This was a cohort study assessing the incidence of myocardial infarction 365 days after blood culture for Staphylococcus aureus. Culture-negative patients had blood cultures collected at hospital attendance and were matched to the CA-SABSI participants by sex, 5-year age strata, and year of culture collection. Pathology information was linked to hospital administrative data and index of relative socioeconomic advantage and disadvantage (ISRAD). Results: The study included 5157 CA-SABSI cases matched to 10 146 blood culture-negative cases. The mortality rate was significantly higher in the CA-SABSI group (10.9%; 562/5157) than in culture-negative cases (5.1%; 521/10 146) at 365 days (P<.0001). In the 7 days following the index blood culture, excluding recurrent events, there were 89 (1.7%) and 37 (.4%) myocardial infarction diagnoses in the CA-SABSI and culture-negative cases, respectively. Multivariable logistic regression for myocardial infarction demonstrated a significant association with CA-SABSI after adjusting for known risk factors (odds ratio [OR], 5; 95% confidence interval [CI], 3.3-7.5; P<.0001). Myocardial infarctions occurring in this short-term risk period were associated with all-cause mortality in a Cox proportional hazard model (OR, 1.7; 95% CI, 1.2-2.4; P<.005). Conclusions: CA-SABSI is associated with an increased short-term risk of myocardial infarction, which is associated with subsequent mortality.