Predictors of one-year all-cause mortality and infection-related mortality in patients with Staphylococcus aureus...

Staphylococcus aureus bacteraemia (SAB) is a common infection associated with significant short-term mortality. Little is known about long-term prognosis. The aim of this study was to determine one-year all-cause mortality and infection-related mortality and associated predictors.

Data from 303 consecutive patients with SAB were prospectively collected from March 2011 to February 2014. All patients were followed one year or until death.

One-year all-cause- and infection-related mortality were 36.7% and 20.8%, respectively. For all-cause mortality, in multivariable logistic regression analysis, age 70-79 years (OR 3.9; 95% CI 1.7-9.1; p = .001), Charlson Comorbidity index ≥3 (OR 6.9; 95% CI 2.7-17.3; p < .001), healthcare-associated infection (OR 2.3; 95% CI 1.1-4.9; p = .03) and severe sepsis (OR 3.6; 95% CI 1.8-7.1; p < .001) were independent predictors of outcome. For infection-related mortality, the predictors were similar, except for healthcare-associated infection that lost significance. The vast majority (89%) of infection-related deaths occurred within 30 days.

This study demonstrates additional significant all-cause mortality in patients with SAB beyond 30 days to one year, mainly driven by high age and comorbidity. As a result, SAB can be considered an indirect marker of high risk of death in these patients. Follow-up beyond 30 days does not add significant information with respect to infection-related mortality.