All-cause and Infection-attributable Mortality Amongst Adults With Bloodstream Infection-a Population-based Study.

Area of Science:

• Infectious Diseases
• Epidemiology
• Public Health

Background:

• Bloodstream infections (BSIs) are significant causes of mortality.
• The primary cause of death following BSIs, whether infection-related or due to comorbidities, requires clarification.

Purpose of the Study:

• To determine overall mortality, infection-attributable mortality, and causes of death for four common BSI pathogens.
• To compare mortality rates associated with *Escherichia coli*, *Klebsiella* spp., *Pseudomonas aeruginosa*, and *Staphylococcus aureus* BSIs.

Main Methods:

• Retrospective cohort study using UK electronic health records (2010-2022).
• Included adults with BSIs from *E. coli*, *Klebsiella* spp., *P. aeruginosa*, and *S. aureus*.
• Analyzed 30-day all-cause and sepsis-specific mortality using Cox regression and competing risk models.

Main Results:

• *P. aeruginosa* BSI was associated with the highest 30-day mortality (HR 1.96).
• Cancer was the leading cause of death post-BSI, especially between 30-90 days (35.9%).
• Sepsis accounted for 25.5% of 30-day deaths; Methicillin-resistant *S. aureus* (MRSA) had higher sepsis mortality (HR 2.56).

Conclusions:

• Most BSI deaths are not solely due to uncontrolled infection, particularly in the subacute phase (>30 days).
• Findings suggest a need to re-evaluate clinical trial designs for BSIs.
• Improved preventive strategies for BSIs are essential.