Heterogeneity in Staphylococcus aureus Bacteraemia Clinical Trials Complicates Interpretation of Findings

We systematically evaluated randomized-controlled trials (RCTs) for Staphylococcus aureus bacteremia (SAB). There was intertrial heterogeneity in cohort characteristics, including bacteremia source, complicated SAB, and comorbidities. Reporting of cohort characteristics was itself variable, including bacteremia source and illness severity. Selection bias was introduced by exclusion criteria relating to comorbidities, illness severity, infection types, and source control. Mortality was lower in RCT control arms compared with observational cohorts. Differences in outcome definitions impedes meta-analysis. These issues complicate the interpretation and application of SAB RCT results. The value of these trials should be maximized by a standardized approach to recruitment, definitions, and reporting. RCTs of medical therapy for SAB contain intertrial heterogeneity in clinically important cohort characteristics. Reporting of cohort characteristics and definitions of outcomes are variable. Some exclusion criteria introduce selection biases. These issues complicate the interpretation and application of results.