Predictors of mortality in adult patients with methicillin-resistant Staphylococcus aureus bloodstream infection: a meta-analysis and systematic review.

Background: Cases of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection have been increasing. Patients with MRSA bloodstream infection have a poor prognosis and high mortality rate. Identification of potential risk factors associated with MRSA bloodstream infection-related mortality may help improve patient outcomes.

Methods: Embase, PubMed, and the Cochrane Library databases were searched to identify articles describing predictors of mortality in patients with MRSA bloodstream infections. Two investigators independently assessed articles for inclusion and data extraction.

Results: Twenty observational studies were included in the analysis. Factors associated with higher mortality were development of severe sepsis or septic shock [odds ratio (OR): 4.56, 95% CI: 3.37-6.18], congestive heart failure (OR: 1.78, 95% CI: 1.27-2.50), liver cirrhosis (OR: 1.90, 95% CI: 1.27-2.65), malignancy (OR: 1.62, 95% CI: 1.33-1.98), infective endocarditis (OR: 2.05, 95% CI: 1.35-3.11), nosocomial infection (OR: 2.80, 95% CI: 1.41-5.55), intensive care unit admission (OR: 3.08, 95% CI: 1.49-6.36) and inappropriate empirical antimicrobial treatment (OR: 2.25, 95% CI: 1.16-4.36); removal of the eradicable foci was a protective factor (OR: 0.51, 95% CI: 0.40-0.63) The average APACHE II score at the time of diagnosis of MRSA bloodstream infection was considerably higher in patients who did not survive than in those who survived [weighted mean difference (WMD): 5.81, 95% CI: 3.03-8.59].

Discussion: Patient condition, appropriate timing of antimicrobial treatment, surgical intervention and disease severity according to the APACHE II score are the most important risk factors for death in patients with MRSA bloodstream infections.