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

Abstract

Objectives: 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.Methods: 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.Results: 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.Conclusions: 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.