Long-term mortality following bloodstream infection

Abstract

Bloodstream infection is associated with significant short-term mortality, but less is known about long-term outcome. We describe factors affecting mortality up to 3 years after bloodstream infection in a cohort of patients reviewed at the bedside by an infection specialist. Patients seen by the bacteraemia service of our infectious diseases department between June 2005 and November 2008 were included in analyses. Routine clinical data collected at the time of consultation, together with laboratory, demographic and outcome data were analysed to identify factors predicting death at 30 days and 3 years after bloodstream infection. Cox regression models for both time-points were constructed, together with Kaplan-Meier survival curves. In all, 322 bloodstream infections were recorded in 304 patients. The 30-day mortality was 15%, with a 3-year mortality of 49%. At 30 days after bacteraemia, in the Cox regression model, increasing age (p 0.003) and lower serum albumin (p 0.014) were predictive of death. At 3 years, age (p <0.0001) and albumin (p 0.004) remained significant predictors of death, with the presence of vascular disease (p 0.05) also significantly associated with mortality. If temperature was treated as a continuous variable then urea was significant (p 0.044); however, if temperature was categorized into hypothermia and non-hypothermia, then the presence of hypothermia (p 0.008) and chronic renal disease (p 0.034) became significant. There is an appreciable and gradual increase in mortality after an episode of bloodstream infection. Although many factors may not be amenable to intervention, patients at high risk of long-term mortality might require further follow up and assessment for potentially modifiable factors.

Keywords: Bacteraemia; co-morbidity; fever; long-term; mortality.